# HG changeset patch # User dl # Date 1370379563 -3600 # Node ID 97634ef9dd1ceed3892927f0db29efe62ed1905c # Parent bbd67fc49daa58d708417d6b3cf74ed3fa24e651 8005704: Update ConcurrentHashMap to v8 Reviewed-by: chegar, mduigou diff -r bbd67fc49daa -r 97634ef9dd1c jdk/src/share/classes/java/util/concurrent/ConcurrentHashMap.java --- a/jdk/src/share/classes/java/util/concurrent/ConcurrentHashMap.java Tue Jun 04 10:33:13 2013 -0700 +++ b/jdk/src/share/classes/java/util/concurrent/ConcurrentHashMap.java Tue Jun 04 21:59:23 2013 +0100 @@ -34,14 +34,47 @@ */ package java.util.concurrent; -import java.io.ObjectInputStream; -import java.util.concurrent.locks.*; -import java.util.*; import java.io.Serializable; +import java.io.ObjectStreamField; +import java.lang.reflect.ParameterizedType; +import java.lang.reflect.Type; +import java.util.AbstractMap; +import java.util.Arrays; +import java.util.Collection; +import java.util.Comparator; +import java.util.ConcurrentModificationException; +import java.util.Enumeration; +import java.util.HashMap; +import java.util.Hashtable; +import java.util.Iterator; +import java.util.Map; +import java.util.NoSuchElementException; +import java.util.Set; +import java.util.Spliterator; +import java.util.concurrent.ConcurrentMap; +import java.util.concurrent.ForkJoinPool; +import java.util.concurrent.atomic.AtomicReference; +import java.util.concurrent.locks.ReentrantLock; +import java.util.concurrent.locks.StampedLock; +import java.util.function.BiConsumer; +import java.util.function.BiFunction; +import java.util.function.BinaryOperator; +import java.util.function.Consumer; +import java.util.function.DoubleBinaryOperator; +import java.util.function.Function; +import java.util.function.IntBinaryOperator; +import java.util.function.LongBinaryOperator; +import java.util.function.ToDoubleBiFunction; +import java.util.function.ToDoubleFunction; +import java.util.function.ToIntBiFunction; +import java.util.function.ToIntFunction; +import java.util.function.ToLongBiFunction; +import java.util.function.ToLongFunction; +import java.util.stream.Stream; /** * A hash table supporting full concurrency of retrievals and - * adjustable expected concurrency for updates. This class obeys the + * high expected concurrency for updates. This class obeys the * same functional specification as {@link java.util.Hashtable}, and * includes versions of methods corresponding to each method of * {@code Hashtable}. However, even though all operations are @@ -51,35 +84,61 @@ * interoperable with {@code Hashtable} in programs that rely on its * thread safety but not on its synchronization details. * - *

Retrieval operations (including {@code get}) generally do not - * block, so may overlap with update operations (including - * {@code put} and {@code remove}). Retrievals reflect the results - * of the most recently completed update operations holding - * upon their onset. For aggregate operations such as {@code putAll} - * and {@code clear}, concurrent retrievals may reflect insertion or - * removal of only some entries. Similarly, Iterators and - * Enumerations return elements reflecting the state of the hash table - * at some point at or since the creation of the iterator/enumeration. - * They do not throw {@link ConcurrentModificationException}. - * However, iterators are designed to be used by only one thread at a time. + *

Retrieval operations (including {@code get}) generally do not + * block, so may overlap with update operations (including {@code put} + * and {@code remove}). Retrievals reflect the results of the most + * recently completed update operations holding upon their + * onset. (More formally, an update operation for a given key bears a + * happens-before relation with any (non-null) retrieval for + * that key reporting the updated value.) For aggregate operations + * such as {@code putAll} and {@code clear}, concurrent retrievals may + * reflect insertion or removal of only some entries. Similarly, + * Iterators and Enumerations return elements reflecting the state of + * the hash table at some point at or since the creation of the + * iterator/enumeration. They do not throw {@link + * ConcurrentModificationException}. However, iterators are designed + * to be used by only one thread at a time. Bear in mind that the + * results of aggregate status methods including {@code size}, {@code + * isEmpty}, and {@code containsValue} are typically useful only when + * a map is not undergoing concurrent updates in other threads. + * Otherwise the results of these methods reflect transient states + * that may be adequate for monitoring or estimation purposes, but not + * for program control. * - *

The allowed concurrency among update operations is guided by - * the optional {@code concurrencyLevel} constructor argument - * (default {@code 16}), which is used as a hint for internal sizing. The - * table is internally partitioned to try to permit the indicated - * number of concurrent updates without contention. Because placement - * in hash tables is essentially random, the actual concurrency will - * vary. Ideally, you should choose a value to accommodate as many - * threads as will ever concurrently modify the table. Using a - * significantly higher value than you need can waste space and time, - * and a significantly lower value can lead to thread contention. But - * overestimates and underestimates within an order of magnitude do - * not usually have much noticeable impact. A value of one is - * appropriate when it is known that only one thread will modify and - * all others will only read. Also, resizing this or any other kind of - * hash table is a relatively slow operation, so, when possible, it is - * a good idea to provide estimates of expected table sizes in - * constructors. + *

The table is dynamically expanded when there are too many + * collisions (i.e., keys that have distinct hash codes but fall into + * the same slot modulo the table size), with the expected average + * effect of maintaining roughly two bins per mapping (corresponding + * to a 0.75 load factor threshold for resizing). There may be much + * variance around this average as mappings are added and removed, but + * overall, this maintains a commonly accepted time/space tradeoff for + * hash tables. However, resizing this or any other kind of hash + * table may be a relatively slow operation. When possible, it is a + * good idea to provide a size estimate as an optional {@code + * initialCapacity} constructor argument. An additional optional + * {@code loadFactor} constructor argument provides a further means of + * customizing initial table capacity by specifying the table density + * to be used in calculating the amount of space to allocate for the + * given number of elements. Also, for compatibility with previous + * versions of this class, constructors may optionally specify an + * expected {@code concurrencyLevel} as an additional hint for + * internal sizing. Note that using many keys with exactly the same + * {@code hashCode()} is a sure way to slow down performance of any + * hash table. To ameliorate impact, when keys are {@link Comparable}, + * this class may use comparison order among keys to help break ties. + * + *

A {@link Set} projection of a ConcurrentHashMap may be created + * (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed + * (using {@link #keySet(Object)} when only keys are of interest, and the + * mapped values are (perhaps transiently) not used or all take the + * same mapping value. + * + *

A ConcurrentHashMap can be used as scalable frequency map (a + * form of histogram or multiset) by using {@link + * java.util.concurrent.atomic.LongAdder} values and initializing via + * {@link #computeIfAbsent computeIfAbsent}. For example, to add a count + * to a {@code ConcurrentHashMap freqs}, you can use + * {@code freqs.computeIfAbsent(k -> new LongAdder()).increment();} * *

This class and its views and iterators implement all of the * optional methods of the {@link Map} and {@link Iterator} @@ -88,6 +147,114 @@ *

Like {@link Hashtable} but unlike {@link HashMap}, this class * does not allow {@code null} to be used as a key or value. * + *

ConcurrentHashMaps support a set of sequential and parallel bulk + * operations that, unlike most {@link Stream} methods, are designed + * to be safely, and often sensibly, applied even with maps that are + * being concurrently updated by other threads; for example, when + * computing a snapshot summary of the values in a shared registry. + * There are three kinds of operation, each with four forms, accepting + * functions with Keys, Values, Entries, and (Key, Value) arguments + * and/or return values. Because the elements of a ConcurrentHashMap + * are not ordered in any particular way, and may be processed in + * different orders in different parallel executions, the correctness + * of supplied functions should not depend on any ordering, or on any + * other objects or values that may transiently change while + * computation is in progress; and except for forEach actions, should + * ideally be side-effect-free. Bulk operations on {@link java.util.Map.Entry} + * objects do not support method {@code setValue}. + * + *

+ * + *

These bulk operations accept a {@code parallelismThreshold} + * argument. Methods proceed sequentially if the current map size is + * estimated to be less than the given threshold. Using a value of + * {@code Long.MAX_VALUE} suppresses all parallelism. Using a value + * of {@code 1} results in maximal parallelism by partitioning into + * enough subtasks to fully utilize the {@link + * ForkJoinPool#commonPool()} that is used for all parallel + * computations. Normally, you would initially choose one of these + * extreme values, and then measure performance of using in-between + * values that trade off overhead versus throughput. + * + *

The concurrency properties of bulk operations follow + * from those of ConcurrentHashMap: Any non-null result returned + * from {@code get(key)} and related access methods bears a + * happens-before relation with the associated insertion or + * update. The result of any bulk operation reflects the + * composition of these per-element relations (but is not + * necessarily atomic with respect to the map as a whole unless it + * is somehow known to be quiescent). Conversely, because keys + * and values in the map are never null, null serves as a reliable + * atomic indicator of the current lack of any result. To + * maintain this property, null serves as an implicit basis for + * all non-scalar reduction operations. For the double, long, and + * int versions, the basis should be one that, when combined with + * any other value, returns that other value (more formally, it + * should be the identity element for the reduction). Most common + * reductions have these properties; for example, computing a sum + * with basis 0 or a minimum with basis MAX_VALUE. + * + *

Search and transformation functions provided as arguments + * should similarly return null to indicate the lack of any result + * (in which case it is not used). In the case of mapped + * reductions, this also enables transformations to serve as + * filters, returning null (or, in the case of primitive + * specializations, the identity basis) if the element should not + * be combined. You can create compound transformations and + * filterings by composing them yourself under this "null means + * there is nothing there now" rule before using them in search or + * reduce operations. + * + *

Methods accepting and/or returning Entry arguments maintain + * key-value associations. They may be useful for example when + * finding the key for the greatest value. Note that "plain" Entry + * arguments can be supplied using {@code new + * AbstractMap.SimpleEntry(k,v)}. + * + *

Bulk operations may complete abruptly, throwing an + * exception encountered in the application of a supplied + * function. Bear in mind when handling such exceptions that other + * concurrently executing functions could also have thrown + * exceptions, or would have done so if the first exception had + * not occurred. + * + *

Speedups for parallel compared to sequential forms are common + * but not guaranteed. Parallel operations involving brief functions + * on small maps may execute more slowly than sequential forms if the + * underlying work to parallelize the computation is more expensive + * than the computation itself. Similarly, parallelization may not + * lead to much actual parallelism if all processors are busy + * performing unrelated tasks. + * + *

All arguments to all task methods must be non-null. + * *

This class is a member of the * * Java Collections Framework. @@ -97,735 +264,2371 @@ * @param the type of keys maintained by this map * @param the type of mapped values */ -public class ConcurrentHashMap extends AbstractMap - implements ConcurrentMap, Serializable { +@SuppressWarnings({"unchecked", "rawtypes", "serial"}) +public class ConcurrentHashMap extends AbstractMap + implements ConcurrentMap, Serializable { + private static final long serialVersionUID = 7249069246763182397L; /* - * The basic strategy is to subdivide the table among Segments, - * each of which itself is a concurrently readable hash table. To - * reduce footprint, all but one segments are constructed only - * when first needed (see ensureSegment). To maintain visibility - * in the presence of lazy construction, accesses to segments as - * well as elements of segment's table must use volatile access, - * which is done via Unsafe within methods segmentAt etc - * below. These provide the functionality of AtomicReferenceArrays - * but reduce the levels of indirection. Additionally, - * volatile-writes of table elements and entry "next" fields - * within locked operations use the cheaper "lazySet" forms of - * writes (via putOrderedObject) because these writes are always - * followed by lock releases that maintain sequential consistency - * of table updates. + * Overview: + * + * The primary design goal of this hash table is to maintain + * concurrent readability (typically method get(), but also + * iterators and related methods) while minimizing update + * contention. Secondary goals are to keep space consumption about + * the same or better than java.util.HashMap, and to support high + * initial insertion rates on an empty table by many threads. + * + * Each key-value mapping is held in a Node. Because Node key + * fields can contain special values, they are defined using plain + * Object types (not type "K"). This leads to a lot of explicit + * casting (and the use of class-wide warning suppressions). It + * also allows some of the public methods to be factored into a + * smaller number of internal methods (although sadly not so for + * the five variants of put-related operations). The + * validation-based approach explained below leads to a lot of + * code sprawl because retry-control precludes factoring into + * smaller methods. + * + * The table is lazily initialized to a power-of-two size upon the + * first insertion. Each bin in the table normally contains a + * list of Nodes (most often, the list has only zero or one Node). + * Table accesses require volatile/atomic reads, writes, and + * CASes. Because there is no other way to arrange this without + * adding further indirections, we use intrinsics + * (sun.misc.Unsafe) operations. + * + * We use the top (sign) bit of Node hash fields for control + * purposes -- it is available anyway because of addressing + * constraints. Nodes with negative hash fields are forwarding + * nodes to either TreeBins or resized tables. The lower 31 bits + * of each normal Node's hash field contain a transformation of + * the key's hash code. + * + * Insertion (via put or its variants) of the first node in an + * empty bin is performed by just CASing it to the bin. This is + * by far the most common case for put operations under most + * key/hash distributions. Other update operations (insert, + * delete, and replace) require locks. We do not want to waste + * the space required to associate a distinct lock object with + * each bin, so instead use the first node of a bin list itself as + * a lock. Locking support for these locks relies on builtin + * "synchronized" monitors. + * + * Using the first node of a list as a lock does not by itself + * suffice though: When a node is locked, any update must first + * validate that it is still the first node after locking it, and + * retry if not. Because new nodes are always appended to lists, + * once a node is first in a bin, it remains first until deleted + * or the bin becomes invalidated (upon resizing). + * + * The main disadvantage of per-bin locks is that other update + * operations on other nodes in a bin list protected by the same + * lock can stall, for example when user equals() or mapping + * functions take a long time. However, statistically, under + * random hash codes, this is not a common problem. Ideally, the + * frequency of nodes in bins follows a Poisson distribution + * (http://en.wikipedia.org/wiki/Poisson_distribution) with a + * parameter of about 0.5 on average, given the resizing threshold + * of 0.75, although with a large variance because of resizing + * granularity. Ignoring variance, the expected occurrences of + * list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The + * first values are: + * + * 0: 0.60653066 + * 1: 0.30326533 + * 2: 0.07581633 + * 3: 0.01263606 + * 4: 0.00157952 + * 5: 0.00015795 + * 6: 0.00001316 + * 7: 0.00000094 + * 8: 0.00000006 + * more: less than 1 in ten million + * + * Lock contention probability for two threads accessing distinct + * elements is roughly 1 / (8 * #elements) under random hashes. * - * Historical note: The previous version of this class relied - * heavily on "final" fields, which avoided some volatile reads at - * the expense of a large initial footprint. Some remnants of - * that design (including forced construction of segment 0) exist - * to ensure serialization compatibility. + * Actual hash code distributions encountered in practice + * sometimes deviate significantly from uniform randomness. This + * includes the case when N > (1<<30), so some keys MUST collide. + * Similarly for dumb or hostile usages in which multiple keys are + * designed to have identical hash codes. Also, although we guard + * against the worst effects of this (see method spread), sets of + * hashes may differ only in bits that do not impact their bin + * index for a given power-of-two mask. So we use a secondary + * strategy that applies when the number of nodes in a bin exceeds + * a threshold, and at least one of the keys implements + * Comparable. These TreeBins use a balanced tree to hold nodes + * (a specialized form of red-black trees), bounding search time + * to O(log N). Each search step in a TreeBin is at least twice as + * slow as in a regular list, but given that N cannot exceed + * (1<<64) (before running out of addresses) this bounds search + * steps, lock hold times, etc, to reasonable constants (roughly + * 100 nodes inspected per operation worst case) so long as keys + * are Comparable (which is very common -- String, Long, etc). + * TreeBin nodes (TreeNodes) also maintain the same "next" + * traversal pointers as regular nodes, so can be traversed in + * iterators in the same way. + * + * The table is resized when occupancy exceeds a percentage + * threshold (nominally, 0.75, but see below). Any thread + * noticing an overfull bin may assist in resizing after the + * initiating thread allocates and sets up the replacement + * array. However, rather than stalling, these other threads may + * proceed with insertions etc. The use of TreeBins shields us + * from the worst case effects of overfilling while resizes are in + * progress. Resizing proceeds by transferring bins, one by one, + * from the table to the next table. To enable concurrency, the + * next table must be (incrementally) prefilled with place-holders + * serving as reverse forwarders to the old table. Because we are + * using power-of-two expansion, the elements from each bin must + * either stay at same index, or move with a power of two + * offset. We eliminate unnecessary node creation by catching + * cases where old nodes can be reused because their next fields + * won't change. On average, only about one-sixth of them need + * cloning when a table doubles. The nodes they replace will be + * garbage collectable as soon as they are no longer referenced by + * any reader thread that may be in the midst of concurrently + * traversing table. Upon transfer, the old table bin contains + * only a special forwarding node (with hash field "MOVED") that + * contains the next table as its key. On encountering a + * forwarding node, access and update operations restart, using + * the new table. + * + * Each bin transfer requires its bin lock, which can stall + * waiting for locks while resizing. However, because other + * threads can join in and help resize rather than contend for + * locks, average aggregate waits become shorter as resizing + * progresses. The transfer operation must also ensure that all + * accessible bins in both the old and new table are usable by any + * traversal. This is arranged by proceeding from the last bin + * (table.length - 1) up towards the first. Upon seeing a + * forwarding node, traversals (see class Traverser) arrange to + * move to the new table without revisiting nodes. However, to + * ensure that no intervening nodes are skipped, bin splitting can + * only begin after the associated reverse-forwarders are in + * place. + * + * The traversal scheme also applies to partial traversals of + * ranges of bins (via an alternate Traverser constructor) + * to support partitioned aggregate operations. Also, read-only + * operations give up if ever forwarded to a null table, which + * provides support for shutdown-style clearing, which is also not + * currently implemented. + * + * Lazy table initialization minimizes footprint until first use, + * and also avoids resizings when the first operation is from a + * putAll, constructor with map argument, or deserialization. + * These cases attempt to override the initial capacity settings, + * but harmlessly fail to take effect in cases of races. + * + * The element count is maintained using a specialization of + * LongAdder. We need to incorporate a specialization rather than + * just use a LongAdder in order to access implicit + * contention-sensing that leads to creation of multiple + * Cells. The counter mechanics avoid contention on + * updates but can encounter cache thrashing if read too + * frequently during concurrent access. To avoid reading so often, + * resizing under contention is attempted only upon adding to a + * bin already holding two or more nodes. Under uniform hash + * distributions, the probability of this occurring at threshold + * is around 13%, meaning that only about 1 in 8 puts check + * threshold (and after resizing, many fewer do so). The bulk + * putAll operation further reduces contention by only committing + * count updates upon these size checks. + * + * Maintaining API and serialization compatibility with previous + * versions of this class introduces several oddities. Mainly: We + * leave untouched but unused constructor arguments refering to + * concurrencyLevel. We accept a loadFactor constructor argument, + * but apply it only to initial table capacity (which is the only + * time that we can guarantee to honor it.) We also declare an + * unused "Segment" class that is instantiated in minimal form + * only when serializing. */ /* ---------------- Constants -------------- */ /** - * The default initial capacity for this table, - * used when not otherwise specified in a constructor. + * The largest possible table capacity. This value must be + * exactly 1<<30 to stay within Java array allocation and indexing + * bounds for power of two table sizes, and is further required + * because the top two bits of 32bit hash fields are used for + * control purposes. */ - static final int DEFAULT_INITIAL_CAPACITY = 16; + private static final int MAXIMUM_CAPACITY = 1 << 30; + + /** + * The default initial table capacity. Must be a power of 2 + * (i.e., at least 1) and at most MAXIMUM_CAPACITY. + */ + private static final int DEFAULT_CAPACITY = 16; /** - * The default load factor for this table, used when not - * otherwise specified in a constructor. + * The largest possible (non-power of two) array size. + * Needed by toArray and related methods. */ - static final float DEFAULT_LOAD_FACTOR = 0.75f; + static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; /** - * The default concurrency level for this table, used when not - * otherwise specified in a constructor. + * The default concurrency level for this table. Unused but + * defined for compatibility with previous versions of this class. */ - static final int DEFAULT_CONCURRENCY_LEVEL = 16; + private static final int DEFAULT_CONCURRENCY_LEVEL = 16; + + /** + * The load factor for this table. Overrides of this value in + * constructors affect only the initial table capacity. The + * actual floating point value isn't normally used -- it is + * simpler to use expressions such as {@code n - (n >>> 2)} for + * the associated resizing threshold. + */ + private static final float LOAD_FACTOR = 0.75f; /** - * The maximum capacity, used if a higher value is implicitly - * specified by either of the constructors with arguments. MUST - * be a power of two <= 1<<30 to ensure that entries are indexable - * using ints. + * The bin count threshold for using a tree rather than list for a + * bin. The value reflects the approximate break-even point for + * using tree-based operations. */ - static final int MAXIMUM_CAPACITY = 1 << 30; + private static final int TREE_THRESHOLD = 8; /** - * The minimum capacity for per-segment tables. Must be a power - * of two, at least two to avoid immediate resizing on next use - * after lazy construction. + * Minimum number of rebinnings per transfer step. Ranges are + * subdivided to allow multiple resizer threads. This value + * serves as a lower bound to avoid resizers encountering + * excessive memory contention. The value should be at least + * DEFAULT_CAPACITY. + */ + private static final int MIN_TRANSFER_STRIDE = 16; + + /* + * Encodings for Node hash fields. See above for explanation. */ - static final int MIN_SEGMENT_TABLE_CAPACITY = 2; + static final int MOVED = 0x80000000; // hash field for forwarding nodes + static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash + + /** Number of CPUS, to place bounds on some sizings */ + static final int NCPU = Runtime.getRuntime().availableProcessors(); + + /** For serialization compatibility. */ + private static final ObjectStreamField[] serialPersistentFields = { + new ObjectStreamField("segments", Segment[].class), + new ObjectStreamField("segmentMask", Integer.TYPE), + new ObjectStreamField("segmentShift", Integer.TYPE) + }; /** - * The maximum number of segments to allow; used to bound - * constructor arguments. Must be power of two less than 1 << 24. + * A padded cell for distributing counts. Adapted from LongAdder + * and Striped64. See their internal docs for explanation. */ - static final int MAX_SEGMENTS = 1 << 16; // slightly conservative - - /** - * Number of unsynchronized retries in size and containsValue - * methods before resorting to locking. This is used to avoid - * unbounded retries if tables undergo continuous modification - * which would make it impossible to obtain an accurate result. - */ - static final int RETRIES_BEFORE_LOCK = 2; + @sun.misc.Contended static final class Cell { + volatile long value; + Cell(long x) { value = x; } + } /* ---------------- Fields -------------- */ /** - * A randomizing value associated with this instance that is applied to - * hash code of keys to make hash collisions harder to find. + * The array of bins. Lazily initialized upon first insertion. + * Size is always a power of two. Accessed directly by iterators. + */ + transient volatile Node[] table; + + /** + * The next table to use; non-null only while resizing. + */ + private transient volatile Node[] nextTable; + + /** + * Base counter value, used mainly when there is no contention, + * but also as a fallback during table initialization + * races. Updated via CAS. + */ + private transient volatile long baseCount; + + /** + * Table initialization and resizing control. When negative, the + * table is being initialized or resized: -1 for initialization, + * else -(1 + the number of active resizing threads). Otherwise, + * when table is null, holds the initial table size to use upon + * creation, or 0 for default. After initialization, holds the + * next element count value upon which to resize the table. + */ + private transient volatile int sizeCtl; + + /** + * The next table index (plus one) to split while resizing. + */ + private transient volatile int transferIndex; + + /** + * The least available table index to split while resizing. + */ + private transient volatile int transferOrigin; + + /** + * Spinlock (locked via CAS) used when resizing and/or creating Cells. */ - private transient final int hashSeed = sun.misc.Hashing.randomHashSeed(this); + private transient volatile int cellsBusy; + + /** + * Table of counter cells. When non-null, size is a power of 2. + */ + private transient volatile Cell[] counterCells; + + // views + private transient KeySetView keySet; + private transient ValuesView values; + private transient EntrySetView entrySet; + + /* ---------------- Table element access -------------- */ + + /* + * Volatile access methods are used for table elements as well as + * elements of in-progress next table while resizing. Uses are + * null checked by callers, and implicitly bounds-checked, relying + * on the invariants that tab arrays have non-zero size, and all + * indices are masked with (tab.length - 1) which is never + * negative and always less than length. Note that, to be correct + * wrt arbitrary concurrency errors by users, bounds checks must + * operate on local variables, which accounts for some odd-looking + * inline assignments below. + */ + + static final Node tabAt(Node[] tab, int i) { + return (Node)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE); + } + + static final boolean casTabAt(Node[] tab, int i, + Node c, Node v) { + return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v); + } + + static final void setTabAt(Node[] tab, int i, Node v) { + U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v); + } + + /* ---------------- Nodes -------------- */ /** - * Mask value for indexing into segments. The upper bits of a - * key's hash code are used to choose the segment. + * Key-value entry. This class is never exported out as a + * user-mutable Map.Entry (i.e., one supporting setValue; see + * MapEntry below), but can be used for read-only traversals used + * in bulk tasks. Nodes with a hash field of MOVED are special, + * and do not contain user keys or values (and are never + * exported). Otherwise, keys and vals are never null. */ - final int segmentMask; + static class Node implements Map.Entry { + final int hash; + final Object key; + volatile V val; + Node next; + + Node(int hash, Object key, V val, Node next) { + this.hash = hash; + this.key = key; + this.val = val; + this.next = next; + } + + public final K getKey() { return (K)key; } + public final V getValue() { return val; } + public final int hashCode() { return key.hashCode() ^ val.hashCode(); } + public final String toString(){ return key + "=" + val; } + public final V setValue(V value) { + throw new UnsupportedOperationException(); + } + + public final boolean equals(Object o) { + Object k, v, u; Map.Entry e; + return ((o instanceof Map.Entry) && + (k = (e = (Map.Entry)o).getKey()) != null && + (v = e.getValue()) != null && + (k == key || k.equals(key)) && + (v == (u = val) || v.equals(u))); + } + } /** - * Shift value for indexing within segments. + * Exported Entry for EntryIterator */ - final int segmentShift; + static final class MapEntry implements Map.Entry { + final K key; // non-null + V val; // non-null + final ConcurrentHashMap map; + MapEntry(K key, V val, ConcurrentHashMap map) { + this.key = key; + this.val = val; + this.map = map; + } + public K getKey() { return key; } + public V getValue() { return val; } + public int hashCode() { return key.hashCode() ^ val.hashCode(); } + public String toString() { return key + "=" + val; } + + public boolean equals(Object o) { + Object k, v; Map.Entry e; + return ((o instanceof Map.Entry) && + (k = (e = (Map.Entry)o).getKey()) != null && + (v = e.getValue()) != null && + (k == key || k.equals(key)) && + (v == val || v.equals(val))); + } + + /** + * Sets our entry's value and writes through to the map. The + * value to return is somewhat arbitrary here. Since we do not + * necessarily track asynchronous changes, the most recent + * "previous" value could be different from what we return (or + * could even have been removed, in which case the put will + * re-establish). We do not and cannot guarantee more. + */ + public V setValue(V value) { + if (value == null) throw new NullPointerException(); + V v = val; + val = value; + map.put(key, value); + return v; + } + } + + + /* ---------------- TreeBins -------------- */ + + /** + * Nodes for use in TreeBins + */ + static final class TreeNode extends Node { + TreeNode parent; // red-black tree links + TreeNode left; + TreeNode right; + TreeNode prev; // needed to unlink next upon deletion + boolean red; + + TreeNode(int hash, Object key, V val, Node next, + TreeNode parent) { + super(hash, key, val, next); + this.parent = parent; + } + } + + /** + * Returns a Class for the given type of the form "class C + * implements Comparable", if one exists, else null. See below + * for explanation. + */ + static Class comparableClassFor(Class c) { + Class s, cmpc; Type[] ts, as; Type t; ParameterizedType p; + if (c == String.class) // bypass checks + return c; + if (c != null && (cmpc = Comparable.class).isAssignableFrom(c)) { + while (cmpc.isAssignableFrom(s = c.getSuperclass())) + c = s; // find topmost comparable class + if ((ts = c.getGenericInterfaces()) != null) { + for (int i = 0; i < ts.length; ++i) { + if (((t = ts[i]) instanceof ParameterizedType) && + ((p = (ParameterizedType)t).getRawType() == cmpc) && + (as = p.getActualTypeArguments()) != null && + as.length == 1 && as[0] == c) // type arg is c + return c; + } + } + } + return null; + } /** - * The segments, each of which is a specialized hash table. - */ - final Segment[] segments; - - transient Set keySet; - transient Set> entrySet; - transient Collection values; - - /** - * ConcurrentHashMap list entry. Note that this is never exported - * out as a user-visible Map.Entry. + * A specialized form of red-black tree for use in bins + * whose size exceeds a threshold. + * + * TreeBins use a special form of comparison for search and + * related operations (which is the main reason we cannot use + * existing collections such as TreeMaps). TreeBins contain + * Comparable elements, but may contain others, as well as + * elements that are Comparable but not necessarily Comparable + * for the same T, so we cannot invoke compareTo among them. To + * handle this, the tree is ordered primarily by hash value, then + * by Comparable.compareTo order if applicable. On lookup at a + * node, if elements are not comparable or compare as 0 then both + * left and right children may need to be searched in the case of + * tied hash values. (This corresponds to the full list search + * that would be necessary if all elements were non-Comparable and + * had tied hashes.) The red-black balancing code is updated from + * pre-jdk-collections + * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java) + * based in turn on Cormen, Leiserson, and Rivest "Introduction to + * Algorithms" (CLR). + * + * TreeBins also maintain a separate locking discipline than + * regular bins. Because they are forwarded via special MOVED + * nodes at bin heads (which can never change once established), + * we cannot use those nodes as locks. Instead, TreeBin extends + * StampedLock to support a form of read-write lock. For update + * operations and table validation, the exclusive form of lock + * behaves in the same way as bin-head locks. However, lookups use + * shared read-lock mechanics to allow multiple readers in the + * absence of writers. Additionally, these lookups do not ever + * block: While the lock is not available, they proceed along the + * slow traversal path (via next-pointers) until the lock becomes + * available or the list is exhausted, whichever comes + * first. These cases are not fast, but maximize aggregate + * expected throughput. */ - static final class HashEntry { - final int hash; - final K key; - volatile V value; - volatile HashEntry next; - - HashEntry(int hash, K key, V value, HashEntry next) { - this.hash = hash; - this.key = key; - this.value = value; - this.next = next; + static final class TreeBin extends StampedLock { + private static final long serialVersionUID = 2249069246763182397L; + transient TreeNode root; // root of tree + transient TreeNode first; // head of next-pointer list + + /** From CLR */ + private void rotateLeft(TreeNode p) { + if (p != null) { + TreeNode r = p.right, pp, rl; + if ((rl = p.right = r.left) != null) + rl.parent = p; + if ((pp = r.parent = p.parent) == null) + root = r; + else if (pp.left == p) + pp.left = r; + else + pp.right = r; + r.left = p; + p.parent = r; + } + } + + /** From CLR */ + private void rotateRight(TreeNode p) { + if (p != null) { + TreeNode l = p.left, pp, lr; + if ((lr = p.left = l.right) != null) + lr.parent = p; + if ((pp = l.parent = p.parent) == null) + root = l; + else if (pp.right == p) + pp.right = l; + else + pp.left = l; + l.right = p; + p.parent = l; + } + } + + /** + * Returns the TreeNode (or null if not found) for the given key + * starting at given root. + */ + final TreeNode getTreeNode(int h, Object k, TreeNode p, + Class cc) { + while (p != null) { + int dir, ph; Object pk; Class pc; + if ((ph = p.hash) != h) + dir = (h < ph) ? -1 : 1; + else if ((pk = p.key) == k || k.equals(pk)) + return p; + else if (cc == null || pk == null || + ((pc = pk.getClass()) != cc && + comparableClassFor(pc) != cc) || + (dir = ((Comparable)k).compareTo(pk)) == 0) { + TreeNode r, pr; // check both sides + if ((pr = p.right) != null && + (r = getTreeNode(h, k, pr, cc)) != null) + return r; + else // continue left + dir = -1; + } + p = (dir > 0) ? p.right : p.left; + } + return null; + } + + /** + * Wrapper for getTreeNode used by CHM.get. Tries to obtain + * read-lock to call getTreeNode, but during failure to get + * lock, searches along next links. + */ + final V getValue(int h, Object k) { + Class cc = comparableClassFor(k.getClass()); + Node r = null; + for (Node e = first; e != null; e = e.next) { + long s; + if ((s = tryReadLock()) != 0L) { + try { + r = getTreeNode(h, k, root, cc); + } finally { + unlockRead(s); + } + break; + } + else if (e.hash == h && k.equals(e.key)) { + r = e; + break; + } + } + return r == null ? null : r.val; + } + + /** + * Finds or adds a node. + * @return null if added + */ + final TreeNode putTreeNode(int h, Object k, V v) { + Class cc = comparableClassFor(k.getClass()); + TreeNode pp = root, p = null; + int dir = 0; + while (pp != null) { // find existing node or leaf to insert at + int ph; Object pk; Class pc; + p = pp; + if ((ph = p.hash) != h) + dir = (h < ph) ? -1 : 1; + else if ((pk = p.key) == k || k.equals(pk)) + return p; + else if (cc == null || pk == null || + ((pc = pk.getClass()) != cc && + comparableClassFor(pc) != cc) || + (dir = ((Comparable)k).compareTo(pk)) == 0) { + TreeNode r, pr; + if ((pr = p.right) != null && + (r = getTreeNode(h, k, pr, cc)) != null) + return r; + else // continue left + dir = -1; + } + pp = (dir > 0) ? p.right : p.left; + } + + TreeNode f = first; + TreeNode x = first = new TreeNode(h, k, v, f, p); + if (p == null) + root = x; + else { // attach and rebalance; adapted from CLR + if (f != null) + f.prev = x; + if (dir <= 0) + p.left = x; + else + p.right = x; + x.red = true; + for (TreeNode xp, xpp, xppl, xppr;;) { + if ((xp = x.parent) == null) { + (root = x).red = false; + break; + } + else if (!xp.red || (xpp = xp.parent) == null) { + TreeNode r = root; + if (r != null && r.red) + r.red = false; + break; + } + else if ((xppl = xpp.left) == xp) { + if ((xppr = xpp.right) != null && xppr.red) { + xppr.red = false; + xp.red = false; + xpp.red = true; + x = xpp; + } + else { + if (x == xp.right) { + rotateLeft(x = xp); + xpp = (xp = x.parent) == null ? null : xp.parent; + } + if (xp != null) { + xp.red = false; + if (xpp != null) { + xpp.red = true; + rotateRight(xpp); + } + } + } + } + else { + if (xppl != null && xppl.red) { + xppl.red = false; + xp.red = false; + xpp.red = true; + x = xpp; + } + else { + if (x == xp.left) { + rotateRight(x = xp); + xpp = (xp = x.parent) == null ? null : xp.parent; + } + if (xp != null) { + xp.red = false; + if (xpp != null) { + xpp.red = true; + rotateLeft(xpp); + } + } + } + } + } + } + assert checkInvariants(); + return null; + } + + /** + * Removes the given node, that must be present before this + * call. This is messier than typical red-black deletion code + * because we cannot swap the contents of an interior node + * with a leaf successor that is pinned by "next" pointers + * that are accessible independently of lock. So instead we + * swap the tree linkages. + */ + final void deleteTreeNode(TreeNode p) { + TreeNode next = (TreeNode)p.next; + TreeNode pred = p.prev; // unlink traversal pointers + if (pred == null) + first = next; + else + pred.next = next; + if (next != null) + next.prev = pred; + else if (pred == null) { + root = null; + return; + } + TreeNode replacement; + TreeNode pl = p.left; + TreeNode pr = p.right; + if (pl != null && pr != null) { + TreeNode s = pr, sl; + while ((sl = s.left) != null) // find successor + s = sl; + boolean c = s.red; s.red = p.red; p.red = c; // swap colors + TreeNode sr = s.right; + TreeNode pp = p.parent; + if (s == pr) { // p was s's direct parent + p.parent = s; + s.right = p; + } + else { + TreeNode sp = s.parent; + if ((p.parent = sp) != null) { + if (s == sp.left) + sp.left = p; + else + sp.right = p; + } + if ((s.right = pr) != null) + pr.parent = s; + } + p.left = null; + if ((p.right = sr) != null) + sr.parent = p; + if ((s.left = pl) != null) + pl.parent = s; + if ((s.parent = pp) == null) + root = s; + else if (p == pp.left) + pp.left = s; + else + pp.right = s; + if (sr != null) + replacement = sr; + else + replacement = p; + } + else if (pl != null) + replacement = pl; + else if (pr != null) + replacement = pr; + else + replacement = p; + if (replacement != p) { + TreeNode pp = replacement.parent = p.parent; + if (pp == null) + root = replacement; + else if (p == pp.left) + pp.left = replacement; + else + pp.right = replacement; + p.left = p.right = p.parent = null; + } + if (!p.red) { // rebalance, from CLR + for (TreeNode x = replacement; x != null; ) { + TreeNode xp, xpl, xpr; + if (x.red || (xp = x.parent) == null) { + x.red = false; + break; + } + else if ((xpl = xp.left) == x) { + if ((xpr = xp.right) != null && xpr.red) { + xpr.red = false; + xp.red = true; + rotateLeft(xp); + xpr = (xp = x.parent) == null ? null : xp.right; + } + if (xpr == null) + x = xp; + else { + TreeNode sl = xpr.left, sr = xpr.right; + if ((sr == null || !sr.red) && + (sl == null || !sl.red)) { + xpr.red = true; + x = xp; + } + else { + if (sr == null || !sr.red) { + if (sl != null) + sl.red = false; + xpr.red = true; + rotateRight(xpr); + xpr = (xp = x.parent) == null ? + null : xp.right; + } + if (xpr != null) { + xpr.red = (xp == null) ? false : xp.red; + if ((sr = xpr.right) != null) + sr.red = false; + } + if (xp != null) { + xp.red = false; + rotateLeft(xp); + } + x = root; + } + } + } + else { // symmetric + if (xpl != null && xpl.red) { + xpl.red = false; + xp.red = true; + rotateRight(xp); + xpl = (xp = x.parent) == null ? null : xp.left; + } + if (xpl == null) + x = xp; + else { + TreeNode sl = xpl.left, sr = xpl.right; + if ((sl == null || !sl.red) && + (sr == null || !sr.red)) { + xpl.red = true; + x = xp; + } + else { + if (sl == null || !sl.red) { + if (sr != null) + sr.red = false; + xpl.red = true; + rotateLeft(xpl); + xpl = (xp = x.parent) == null ? + null : xp.left; + } + if (xpl != null) { + xpl.red = (xp == null) ? false : xp.red; + if ((sl = xpl.left) != null) + sl.red = false; + } + if (xp != null) { + xp.red = false; + rotateRight(xp); + } + x = root; + } + } + } + } + } + if (p == replacement) { // detach pointers + TreeNode pp; + if ((pp = p.parent) != null) { + if (p == pp.left) + pp.left = null; + else if (p == pp.right) + pp.right = null; + p.parent = null; + } + } + assert checkInvariants(); + } + + /** + * Checks linkage and balance invariants at root + */ + final boolean checkInvariants() { + TreeNode r = root; + if (r == null) + return (first == null); + else + return (first != null) && checkTreeNode(r); } /** - * Sets next field with volatile write semantics. (See above - * about use of putOrderedObject.) + * Recursive invariant check */ - final void setNext(HashEntry n) { - UNSAFE.putOrderedObject(this, nextOffset, n); + final boolean checkTreeNode(TreeNode t) { + TreeNode tp = t.parent, tl = t.left, tr = t.right, + tb = t.prev, tn = (TreeNode)t.next; + if (tb != null && tb.next != t) + return false; + if (tn != null && tn.prev != t) + return false; + if (tp != null && t != tp.left && t != tp.right) + return false; + if (tl != null && (tl.parent != t || tl.hash > t.hash)) + return false; + if (tr != null && (tr.parent != t || tr.hash < t.hash)) + return false; + if (t.red && tl != null && tl.red && tr != null && tr.red) + return false; + if (tl != null && !checkTreeNode(tl)) + return false; + if (tr != null && !checkTreeNode(tr)) + return false; + return true; + } + } + + /* ---------------- Collision reduction methods -------------- */ + + /** + * Spreads higher bits to lower, and also forces top bit to 0. + * Because the table uses power-of-two masking, sets of hashes + * that vary only in bits above the current mask will always + * collide. (Among known examples are sets of Float keys holding + * consecutive whole numbers in small tables.) To counter this, + * we apply a transform that spreads the impact of higher bits + * downward. There is a tradeoff between speed, utility, and + * quality of bit-spreading. Because many common sets of hashes + * are already reasonably distributed across bits (so don't benefit + * from spreading), and because we use trees to handle large sets + * of collisions in bins, we don't need excessively high quality. + */ + private static final int spread(int h) { + h ^= (h >>> 18) ^ (h >>> 12); + return (h ^ (h >>> 10)) & HASH_BITS; + } + + /** + * Replaces a list bin with a tree bin if key is comparable. Call + * only when locked. + */ + private final void replaceWithTreeBin(Node[] tab, int index, Object key) { + if (tab != null && comparableClassFor(key.getClass()) != null) { + TreeBin t = new TreeBin(); + for (Node e = tabAt(tab, index); e != null; e = e.next) + t.putTreeNode(e.hash, e.key, e.val); + setTabAt(tab, index, new Node(MOVED, t, null, null)); + } + } + + /* ---------------- Internal access and update methods -------------- */ + + /** Implementation for get and containsKey */ + private final V internalGet(Object k) { + int h = spread(k.hashCode()); + V v = null; + Node[] tab; Node e; + if ((tab = table) != null && + (e = tabAt(tab, (tab.length - 1) & h)) != null) { + for (;;) { + int eh; Object ek; + if ((eh = e.hash) < 0) { + if ((ek = e.key) instanceof TreeBin) { // search TreeBin + v = ((TreeBin)ek).getValue(h, k); + break; + } + else if (!(ek instanceof Node[]) || // try new table + (e = tabAt(tab = (Node[])ek, + (tab.length - 1) & h)) == null) + break; + } + else if (eh == h && ((ek = e.key) == k || k.equals(ek))) { + v = e.val; + break; + } + else if ((e = e.next) == null) + break; + } + } + return v; + } + + /** + * Implementation for the four public remove/replace methods: + * Replaces node value with v, conditional upon match of cv if + * non-null. If resulting value is null, delete. + */ + private final V internalReplace(Object k, V v, Object cv) { + int h = spread(k.hashCode()); + V oldVal = null; + for (Node[] tab = table;;) { + Node f; int i, fh; Object fk; + if (tab == null || + (f = tabAt(tab, i = (tab.length - 1) & h)) == null) + break; + else if ((fh = f.hash) < 0) { + if ((fk = f.key) instanceof TreeBin) { + TreeBin t = (TreeBin)fk; + long stamp = t.writeLock(); + boolean validated = false; + boolean deleted = false; + try { + if (tabAt(tab, i) == f) { + validated = true; + Class cc = comparableClassFor(k.getClass()); + TreeNode p = t.getTreeNode(h, k, t.root, cc); + if (p != null) { + V pv = p.val; + if (cv == null || cv == pv || cv.equals(pv)) { + oldVal = pv; + if (v != null) + p.val = v; + else { + deleted = true; + t.deleteTreeNode(p); + } + } + } + } + } finally { + t.unlockWrite(stamp); + } + if (validated) { + if (deleted) + addCount(-1L, -1); + break; + } + } + else + tab = (Node[])fk; + } + else { + boolean validated = false; + boolean deleted = false; + synchronized (f) { + if (tabAt(tab, i) == f) { + validated = true; + for (Node e = f, pred = null;;) { + Object ek; + if (e.hash == h && + ((ek = e.key) == k || k.equals(ek))) { + V ev = e.val; + if (cv == null || cv == ev || cv.equals(ev)) { + oldVal = ev; + if (v != null) + e.val = v; + else { + deleted = true; + Node en = e.next; + if (pred != null) + pred.next = en; + else + setTabAt(tab, i, en); + } + } + break; + } + pred = e; + if ((e = e.next) == null) + break; + } + } + } + if (validated) { + if (deleted) + addCount(-1L, -1); + break; + } + } + } + return oldVal; + } + + /* + * Internal versions of insertion methods + * All have the same basic structure as the first (internalPut): + * 1. If table uninitialized, create + * 2. If bin empty, try to CAS new node + * 3. If bin stale, use new table + * 4. if bin converted to TreeBin, validate and relay to TreeBin methods + * 5. Lock and validate; if valid, scan and add or update + * + * The putAll method differs mainly in attempting to pre-allocate + * enough table space, and also more lazily performs count updates + * and checks. + * + * Most of the function-accepting methods can't be factored nicely + * because they require different functional forms, so instead + * sprawl out similar mechanics. + */ + + /** Implementation for put and putIfAbsent */ + private final V internalPut(K k, V v, boolean onlyIfAbsent) { + if (k == null || v == null) throw new NullPointerException(); + int h = spread(k.hashCode()); + int len = 0; + for (Node[] tab = table;;) { + int i, fh; Node f; Object fk; + if (tab == null) + tab = initTable(); + else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) { + if (casTabAt(tab, i, null, new Node(h, k, v, null))) + break; // no lock when adding to empty bin + } + else if ((fh = f.hash) < 0) { + if ((fk = f.key) instanceof TreeBin) { + TreeBin t = (TreeBin)fk; + long stamp = t.writeLock(); + V oldVal = null; + try { + if (tabAt(tab, i) == f) { + len = 2; + TreeNode p = t.putTreeNode(h, k, v); + if (p != null) { + oldVal = p.val; + if (!onlyIfAbsent) + p.val = v; + } + } + } finally { + t.unlockWrite(stamp); + } + if (len != 0) { + if (oldVal != null) + return oldVal; + break; + } + } + else + tab = (Node[])fk; + } + else { + V oldVal = null; + synchronized (f) { + if (tabAt(tab, i) == f) { + len = 1; + for (Node e = f;; ++len) { + Object ek; + if (e.hash == h && + ((ek = e.key) == k || k.equals(ek))) { + oldVal = e.val; + if (!onlyIfAbsent) + e.val = v; + break; + } + Node last = e; + if ((e = e.next) == null) { + last.next = new Node(h, k, v, null); + if (len > TREE_THRESHOLD) + replaceWithTreeBin(tab, i, k); + break; + } + } + } + } + if (len != 0) { + if (oldVal != null) + return oldVal; + break; + } + } + } + addCount(1L, len); + return null; + } + + /** Implementation for computeIfAbsent */ + private final V internalComputeIfAbsent(K k, Function mf) { + if (k == null || mf == null) + throw new NullPointerException(); + int h = spread(k.hashCode()); + V val = null; + int len = 0; + for (Node[] tab = table;;) { + Node f; int i; Object fk; + if (tab == null) + tab = initTable(); + else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) { + Node node = new Node(h, k, null, null); + synchronized (node) { + if (casTabAt(tab, i, null, node)) { + len = 1; + try { + if ((val = mf.apply(k)) != null) + node.val = val; + } finally { + if (val == null) + setTabAt(tab, i, null); + } + } + } + if (len != 0) + break; + } + else if (f.hash < 0) { + if ((fk = f.key) instanceof TreeBin) { + TreeBin t = (TreeBin)fk; + long stamp = t.writeLock(); + boolean added = false; + try { + if (tabAt(tab, i) == f) { + len = 2; + Class cc = comparableClassFor(k.getClass()); + TreeNode p = t.getTreeNode(h, k, t.root, cc); + if (p != null) + val = p.val; + else if ((val = mf.apply(k)) != null) { + added = true; + t.putTreeNode(h, k, val); + } + } + } finally { + t.unlockWrite(stamp); + } + if (len != 0) { + if (!added) + return val; + break; + } + } + else + tab = (Node[])fk; + } + else { + boolean added = false; + synchronized (f) { + if (tabAt(tab, i) == f) { + len = 1; + for (Node e = f;; ++len) { + Object ek; V ev; + if (e.hash == h && + ((ek = e.key) == k || k.equals(ek))) { + val = e.val; + break; + } + Node last = e; + if ((e = e.next) == null) { + if ((val = mf.apply(k)) != null) { + added = true; + last.next = new Node(h, k, val, null); + if (len > TREE_THRESHOLD) + replaceWithTreeBin(tab, i, k); + } + break; + } + } + } + } + if (len != 0) { + if (!added) + return val; + break; + } + } } - - // Unsafe mechanics - static final sun.misc.Unsafe UNSAFE; - static final long nextOffset; - static { - try { - UNSAFE = sun.misc.Unsafe.getUnsafe(); - Class k = HashEntry.class; - nextOffset = UNSAFE.objectFieldOffset - (k.getDeclaredField("next")); - } catch (Exception e) { - throw new Error(e); + if (val != null) + addCount(1L, len); + return val; + } + + /** Implementation for compute */ + private final V internalCompute(K k, boolean onlyIfPresent, + BiFunction mf) { + if (k == null || mf == null) + throw new NullPointerException(); + int h = spread(k.hashCode()); + V val = null; + int delta = 0; + int len = 0; + for (Node[] tab = table;;) { + Node f; int i, fh; Object fk; + if (tab == null) + tab = initTable(); + else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) { + if (onlyIfPresent) + break; + Node node = new Node(h, k, null, null); + synchronized (node) { + if (casTabAt(tab, i, null, node)) { + try { + len = 1; + if ((val = mf.apply(k, null)) != null) { + node.val = val; + delta = 1; + } + } finally { + if (delta == 0) + setTabAt(tab, i, null); + } + } + } + if (len != 0) + break; + } + else if ((fh = f.hash) < 0) { + if ((fk = f.key) instanceof TreeBin) { + TreeBin t = (TreeBin)fk; + long stamp = t.writeLock(); + try { + if (tabAt(tab, i) == f) { + len = 2; + Class cc = comparableClassFor(k.getClass()); + TreeNode p = t.getTreeNode(h, k, t.root, cc); + if (p != null || !onlyIfPresent) { + V pv = (p == null) ? null : p.val; + if ((val = mf.apply(k, pv)) != null) { + if (p != null) + p.val = val; + else { + delta = 1; + t.putTreeNode(h, k, val); + } + } + else if (p != null) { + delta = -1; + t.deleteTreeNode(p); + } + } + } + } finally { + t.unlockWrite(stamp); + } + if (len != 0) + break; + } + else + tab = (Node[])fk; + } + else { + synchronized (f) { + if (tabAt(tab, i) == f) { + len = 1; + for (Node e = f, pred = null;; ++len) { + Object ek; + if (e.hash == h && + ((ek = e.key) == k || k.equals(ek))) { + val = mf.apply(k, e.val); + if (val != null) + e.val = val; + else { + delta = -1; + Node en = e.next; + if (pred != null) + pred.next = en; + else + setTabAt(tab, i, en); + } + break; + } + pred = e; + if ((e = e.next) == null) { + if (!onlyIfPresent && + (val = mf.apply(k, null)) != null) { + pred.next = new Node(h, k, val, null); + delta = 1; + if (len > TREE_THRESHOLD) + replaceWithTreeBin(tab, i, k); + } + break; + } + } + } + } + if (len != 0) + break; + } + } + if (delta != 0) + addCount((long)delta, len); + return val; + } + + /** Implementation for merge */ + private final V internalMerge(K k, V v, + BiFunction mf) { + if (k == null || v == null || mf == null) + throw new NullPointerException(); + int h = spread(k.hashCode()); + V val = null; + int delta = 0; + int len = 0; + for (Node[] tab = table;;) { + int i; Node f; Object fk; + if (tab == null) + tab = initTable(); + else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) { + if (casTabAt(tab, i, null, new Node(h, k, v, null))) { + delta = 1; + val = v; + break; + } + } + else if (f.hash < 0) { + if ((fk = f.key) instanceof TreeBin) { + TreeBin t = (TreeBin)fk; + long stamp = t.writeLock(); + try { + if (tabAt(tab, i) == f) { + len = 2; + Class cc = comparableClassFor(k.getClass()); + TreeNode p = t.getTreeNode(h, k, t.root, cc); + val = (p == null) ? v : mf.apply(p.val, v); + if (val != null) { + if (p != null) + p.val = val; + else { + delta = 1; + t.putTreeNode(h, k, val); + } + } + else if (p != null) { + delta = -1; + t.deleteTreeNode(p); + } + } + } finally { + t.unlockWrite(stamp); + } + if (len != 0) + break; + } + else + tab = (Node[])fk; + } + else { + synchronized (f) { + if (tabAt(tab, i) == f) { + len = 1; + for (Node e = f, pred = null;; ++len) { + Object ek; + if (e.hash == h && + ((ek = e.key) == k || k.equals(ek))) { + val = mf.apply(e.val, v); + if (val != null) + e.val = val; + else { + delta = -1; + Node en = e.next; + if (pred != null) + pred.next = en; + else + setTabAt(tab, i, en); + } + break; + } + pred = e; + if ((e = e.next) == null) { + delta = 1; + val = v; + pred.next = new Node(h, k, val, null); + if (len > TREE_THRESHOLD) + replaceWithTreeBin(tab, i, k); + break; + } + } + } + } + if (len != 0) + break; + } + } + if (delta != 0) + addCount((long)delta, len); + return val; + } + + /** Implementation for putAll */ + private final void internalPutAll(Map m) { + tryPresize(m.size()); + long delta = 0L; // number of uncommitted additions + boolean npe = false; // to throw exception on exit for nulls + try { // to clean up counts on other exceptions + for (Map.Entry entry : m.entrySet()) { + Object k; V v; + if (entry == null || (k = entry.getKey()) == null || + (v = entry.getValue()) == null) { + npe = true; + break; + } + int h = spread(k.hashCode()); + for (Node[] tab = table;;) { + int i; Node f; int fh; Object fk; + if (tab == null) + tab = initTable(); + else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null){ + if (casTabAt(tab, i, null, new Node(h, k, v, null))) { + ++delta; + break; + } + } + else if ((fh = f.hash) < 0) { + if ((fk = f.key) instanceof TreeBin) { + TreeBin t = (TreeBin)fk; + long stamp = t.writeLock(); + boolean validated = false; + try { + if (tabAt(tab, i) == f) { + validated = true; + Class cc = comparableClassFor(k.getClass()); + TreeNode p = t.getTreeNode(h, k, + t.root, cc); + if (p != null) + p.val = v; + else { + ++delta; + t.putTreeNode(h, k, v); + } + } + } finally { + t.unlockWrite(stamp); + } + if (validated) + break; + } + else + tab = (Node[])fk; + } + else { + int len = 0; + synchronized (f) { + if (tabAt(tab, i) == f) { + len = 1; + for (Node e = f;; ++len) { + Object ek; + if (e.hash == h && + ((ek = e.key) == k || k.equals(ek))) { + e.val = v; + break; + } + Node last = e; + if ((e = e.next) == null) { + ++delta; + last.next = new Node(h, k, v, null); + if (len > TREE_THRESHOLD) + replaceWithTreeBin(tab, i, k); + break; + } + } + } + } + if (len != 0) { + if (len > 1) { + addCount(delta, len); + delta = 0L; + } + break; + } + } + } + } + } finally { + if (delta != 0L) + addCount(delta, 2); + } + if (npe) + throw new NullPointerException(); + } + + /** + * Implementation for clear. Steps through each bin, removing all + * nodes. + */ + private final void internalClear() { + long delta = 0L; // negative number of deletions + int i = 0; + Node[] tab = table; + while (tab != null && i < tab.length) { + Node f = tabAt(tab, i); + if (f == null) + ++i; + else if (f.hash < 0) { + Object fk; + if ((fk = f.key) instanceof TreeBin) { + TreeBin t = (TreeBin)fk; + long stamp = t.writeLock(); + try { + if (tabAt(tab, i) == f) { + for (Node p = t.first; p != null; p = p.next) + --delta; + t.first = null; + t.root = null; + ++i; + } + } finally { + t.unlockWrite(stamp); + } + } + else + tab = (Node[])fk; + } + else { + synchronized (f) { + if (tabAt(tab, i) == f) { + for (Node e = f; e != null; e = e.next) + --delta; + setTabAt(tab, i, null); + ++i; + } + } + } + } + if (delta != 0L) + addCount(delta, -1); + } + + /* ---------------- Table Initialization and Resizing -------------- */ + + /** + * Returns a power of two table size for the given desired capacity. + * See Hackers Delight, sec 3.2 + */ + private static final int tableSizeFor(int c) { + int n = c - 1; + n |= n >>> 1; + n |= n >>> 2; + n |= n >>> 4; + n |= n >>> 8; + n |= n >>> 16; + return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1; + } + + /** + * Initializes table, using the size recorded in sizeCtl. + */ + private final Node[] initTable() { + Node[] tab; int sc; + while ((tab = table) == null) { + if ((sc = sizeCtl) < 0) + Thread.yield(); // lost initialization race; just spin + else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) { + try { + if ((tab = table) == null) { + int n = (sc > 0) ? sc : DEFAULT_CAPACITY; + table = tab = (Node[])new Node[n]; + sc = n - (n >>> 2); + } + } finally { + sizeCtl = sc; + } + break; + } + } + return tab; + } + + /** + * Adds to count, and if table is too small and not already + * resizing, initiates transfer. If already resizing, helps + * perform transfer if work is available. Rechecks occupancy + * after a transfer to see if another resize is already needed + * because resizings are lagging additions. + * + * @param x the count to add + * @param check if <0, don't check resize, if <= 1 only check if uncontended + */ + private final void addCount(long x, int check) { + Cell[] as; long b, s; + if ((as = counterCells) != null || + !U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) { + Cell a; long v; int m; + boolean uncontended = true; + if (as == null || (m = as.length - 1) < 0 || + (a = as[ThreadLocalRandom.getProbe() & m]) == null || + !(uncontended = + U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) { + fullAddCount(x, uncontended); + return; + } + if (check <= 1) + return; + s = sumCount(); + } + if (check >= 0) { + Node[] tab, nt; int sc; + while (s >= (long)(sc = sizeCtl) && (tab = table) != null && + tab.length < MAXIMUM_CAPACITY) { + if (sc < 0) { + if (sc == -1 || transferIndex <= transferOrigin || + (nt = nextTable) == null) + break; + if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1)) + transfer(tab, nt); + } + else if (U.compareAndSwapInt(this, SIZECTL, sc, -2)) + transfer(tab, null); + s = sumCount(); } } } /** - * Gets the ith element of given table (if nonnull) with volatile - * read semantics. Note: This is manually integrated into a few - * performance-sensitive methods to reduce call overhead. - */ - @SuppressWarnings("unchecked") - static final HashEntry entryAt(HashEntry[] tab, int i) { - return (tab == null) ? null : - (HashEntry) UNSAFE.getObjectVolatile - (tab, ((long)i << TSHIFT) + TBASE); - } - - /** - * Sets the ith element of given table, with volatile write - * semantics. (See above about use of putOrderedObject.) + * Tries to presize table to accommodate the given number of elements. + * + * @param size number of elements (doesn't need to be perfectly accurate) */ - static final void setEntryAt(HashEntry[] tab, int i, - HashEntry e) { - UNSAFE.putOrderedObject(tab, ((long)i << TSHIFT) + TBASE, e); - } - - /** - * Applies a supplemental hash function to a given hashCode, which - * defends against poor quality hash functions. This is critical - * because ConcurrentHashMap uses power-of-two length hash tables, - * that otherwise encounter collisions for hashCodes that do not - * differ in lower or upper bits. - */ - private int hash(Object k) { - if (k instanceof String) { - return ((String) k).hash32(); + private final void tryPresize(int size) { + int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : + tableSizeFor(size + (size >>> 1) + 1); + int sc; + while ((sc = sizeCtl) >= 0) { + Node[] tab = table; int n; + if (tab == null || (n = tab.length) == 0) { + n = (sc > c) ? sc : c; + if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) { + try { + if (table == tab) { + table = (Node[])new Node[n]; + sc = n - (n >>> 2); + } + } finally { + sizeCtl = sc; + } + } + } + else if (c <= sc || n >= MAXIMUM_CAPACITY) + break; + else if (tab == table && + U.compareAndSwapInt(this, SIZECTL, sc, -2)) + transfer(tab, null); } - - int h = hashSeed ^ k.hashCode(); - - // Spread bits to regularize both segment and index locations, - // using variant of single-word Wang/Jenkins hash. - h += (h << 15) ^ 0xffffcd7d; - h ^= (h >>> 10); - h += (h << 3); - h ^= (h >>> 6); - h += (h << 2) + (h << 14); - return h ^ (h >>> 16); } /** - * Segments are specialized versions of hash tables. This - * subclasses from ReentrantLock opportunistically, just to - * simplify some locking and avoid separate construction. + * Moves and/or copies the nodes in each bin to new table. See + * above for explanation. */ - static final class Segment extends ReentrantLock implements Serializable { - /* - * Segments maintain a table of entry lists that are always - * kept in a consistent state, so can be read (via volatile - * reads of segments and tables) without locking. This - * requires replicating nodes when necessary during table - * resizing, so the old lists can be traversed by readers - * still using old version of table. - * - * This class defines only mutative methods requiring locking. - * Except as noted, the methods of this class perform the - * per-segment versions of ConcurrentHashMap methods. (Other - * methods are integrated directly into ConcurrentHashMap - * methods.) These mutative methods use a form of controlled - * spinning on contention via methods scanAndLock and - * scanAndLockForPut. These intersperse tryLocks with - * traversals to locate nodes. The main benefit is to absorb - * cache misses (which are very common for hash tables) while - * obtaining locks so that traversal is faster once - * acquired. We do not actually use the found nodes since they - * must be re-acquired under lock anyway to ensure sequential - * consistency of updates (and in any case may be undetectably - * stale), but they will normally be much faster to re-locate. - * Also, scanAndLockForPut speculatively creates a fresh node - * to use in put if no node is found. - */ - - private static final long serialVersionUID = 2249069246763182397L; - - /** - * The maximum number of times to tryLock in a prescan before - * possibly blocking on acquire in preparation for a locked - * segment operation. On multiprocessors, using a bounded - * number of retries maintains cache acquired while locating - * nodes. - */ - static final int MAX_SCAN_RETRIES = - Runtime.getRuntime().availableProcessors() > 1 ? 64 : 1; - - /** - * The per-segment table. Elements are accessed via - * entryAt/setEntryAt providing volatile semantics. - */ - transient volatile HashEntry[] table; - - /** - * The number of elements. Accessed only either within locks - * or among other volatile reads that maintain visibility. - */ - transient int count; - - /** - * The total number of mutative operations in this segment. - * Even though this may overflows 32 bits, it provides - * sufficient accuracy for stability checks in CHM isEmpty() - * and size() methods. Accessed only either within locks or - * among other volatile reads that maintain visibility. - */ - transient int modCount; - - /** - * The table is rehashed when its size exceeds this threshold. - * (The value of this field is always {@code (int)(capacity * - * loadFactor)}.) - */ - transient int threshold; - - /** - * The load factor for the hash table. Even though this value - * is same for all segments, it is replicated to avoid needing - * links to outer object. - * @serial - */ - final float loadFactor; - - Segment(float lf, int threshold, HashEntry[] tab) { - this.loadFactor = lf; - this.threshold = threshold; - this.table = tab; + private final void transfer(Node[] tab, Node[] nextTab) { + int n = tab.length, stride; + if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE) + stride = MIN_TRANSFER_STRIDE; // subdivide range + if (nextTab == null) { // initiating + try { + nextTab = (Node[])new Node[n << 1]; + } catch (Throwable ex) { // try to cope with OOME + sizeCtl = Integer.MAX_VALUE; + return; + } + nextTable = nextTab; + transferOrigin = n; + transferIndex = n; + Node rev = new Node(MOVED, tab, null, null); + for (int k = n; k > 0;) { // progressively reveal ready slots + int nextk = (k > stride) ? k - stride : 0; + for (int m = nextk; m < k; ++m) + nextTab[m] = rev; + for (int m = n + nextk; m < n + k; ++m) + nextTab[m] = rev; + U.putOrderedInt(this, TRANSFERORIGIN, k = nextk); + } } - - final V put(K key, int hash, V value, boolean onlyIfAbsent) { - HashEntry node = tryLock() ? null : - scanAndLockForPut(key, hash, value); - V oldValue; - try { - HashEntry[] tab = table; - int index = (tab.length - 1) & hash; - HashEntry first = entryAt(tab, index); - for (HashEntry e = first;;) { - if (e != null) { - K k; - if ((k = e.key) == key || - (e.hash == hash && key.equals(k))) { - oldValue = e.value; - if (!onlyIfAbsent) { - e.value = value; - ++modCount; - } - break; + int nextn = nextTab.length; + Node fwd = new Node(MOVED, nextTab, null, null); + boolean advance = true; + for (int i = 0, bound = 0;;) { + int nextIndex, nextBound; Node f; Object fk; + while (advance) { + if (--i >= bound) + advance = false; + else if ((nextIndex = transferIndex) <= transferOrigin) { + i = -1; + advance = false; + } + else if (U.compareAndSwapInt + (this, TRANSFERINDEX, nextIndex, + nextBound = (nextIndex > stride ? + nextIndex - stride : 0))) { + bound = nextBound; + i = nextIndex - 1; + advance = false; + } + } + if (i < 0 || i >= n || i + n >= nextn) { + for (int sc;;) { + if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) { + if (sc == -1) { + nextTable = null; + table = nextTab; + sizeCtl = (n << 1) - (n >>> 1); } - e = e.next; - } - else { - if (node != null) - node.setNext(first); - else - node = new HashEntry(hash, key, value, first); - int c = count + 1; - if (c > threshold && tab.length < MAXIMUM_CAPACITY) - rehash(node); - else - setEntryAt(tab, index, node); - ++modCount; - count = c; - oldValue = null; - break; + return; } } - } finally { - unlock(); + } + else if ((f = tabAt(tab, i)) == null) { + if (casTabAt(tab, i, null, fwd)) { + setTabAt(nextTab, i, null); + setTabAt(nextTab, i + n, null); + advance = true; + } } - return oldValue; - } - - /** - * Doubles size of table and repacks entries, also adding the - * given node to new table - */ - @SuppressWarnings("unchecked") - private void rehash(HashEntry node) { - /* - * Reclassify nodes in each list to new table. Because we - * are using power-of-two expansion, the elements from - * each bin must either stay at same index, or move with a - * power of two offset. We eliminate unnecessary node - * creation by catching cases where old nodes can be - * reused because their next fields won't change. - * Statistically, at the default threshold, only about - * one-sixth of them need cloning when a table - * doubles. The nodes they replace will be garbage - * collectable as soon as they are no longer referenced by - * any reader thread that may be in the midst of - * concurrently traversing table. Entry accesses use plain - * array indexing because they are followed by volatile - * table write. - */ - HashEntry[] oldTable = table; - int oldCapacity = oldTable.length; - int newCapacity = oldCapacity << 1; - threshold = (int)(newCapacity * loadFactor); - HashEntry[] newTable = - (HashEntry[]) new HashEntry[newCapacity]; - int sizeMask = newCapacity - 1; - for (int i = 0; i < oldCapacity ; i++) { - HashEntry e = oldTable[i]; - if (e != null) { - HashEntry next = e.next; - int idx = e.hash & sizeMask; - if (next == null) // Single node on list - newTable[idx] = e; - else { // Reuse consecutive sequence at same slot - HashEntry lastRun = e; - int lastIdx = idx; - for (HashEntry last = next; - last != null; - last = last.next) { - int k = last.hash & sizeMask; - if (k != lastIdx) { - lastIdx = k; - lastRun = last; + else if (f.hash >= 0) { + synchronized (f) { + if (tabAt(tab, i) == f) { + int runBit = f.hash & n; + Node lastRun = f, lo = null, hi = null; + for (Node p = f.next; p != null; p = p.next) { + int b = p.hash & n; + if (b != runBit) { + runBit = b; + lastRun = p; } } - newTable[lastIdx] = lastRun; - // Clone remaining nodes - for (HashEntry p = e; p != lastRun; p = p.next) { - V v = p.value; - int h = p.hash; - int k = h & sizeMask; - HashEntry n = newTable[k]; - newTable[k] = new HashEntry(h, p.key, v, n); + if (runBit == 0) + lo = lastRun; + else + hi = lastRun; + for (Node p = f; p != lastRun; p = p.next) { + int ph = p.hash; Object pk = p.key; V pv = p.val; + if ((ph & n) == 0) + lo = new Node(ph, pk, pv, lo); + else + hi = new Node(ph, pk, pv, hi); } + setTabAt(nextTab, i, lo); + setTabAt(nextTab, i + n, hi); + setTabAt(tab, i, fwd); + advance = true; } } } - int nodeIndex = node.hash & sizeMask; // add the new node - node.setNext(newTable[nodeIndex]); - newTable[nodeIndex] = node; - table = newTable; - } - - /** - * Scans for a node containing given key while trying to - * acquire lock, creating and returning one if not found. Upon - * return, guarantees that lock is held. UNlike in most - * methods, calls to method equals are not screened: Since - * traversal speed doesn't matter, we might as well help warm - * up the associated code and accesses as well. - * - * @return a new node if key not found, else null - */ - private HashEntry scanAndLockForPut(K key, int hash, V value) { - HashEntry first = entryForHash(this, hash); - HashEntry e = first; - HashEntry node = null; - int retries = -1; // negative while locating node - while (!tryLock()) { - HashEntry f; // to recheck first below - if (retries < 0) { - if (e == null) { - if (node == null) // speculatively create node - node = new HashEntry(hash, key, value, null); - retries = 0; + else if ((fk = f.key) instanceof TreeBin) { + TreeBin t = (TreeBin)fk; + long stamp = t.writeLock(); + try { + if (tabAt(tab, i) == f) { + TreeNode root; + Node ln = null, hn = null; + if ((root = t.root) != null) { + Node e, p; TreeNode lr, rr; int lh; + TreeBin lt = null, ht = null; + for (lr = root; lr.left != null; lr = lr.left); + for (rr = root; rr.right != null; rr = rr.right); + if ((lh = lr.hash) == rr.hash) { // move entire tree + if ((lh & n) == 0) + lt = t; + else + ht = t; + } + else { + lt = new TreeBin(); + ht = new TreeBin(); + int lc = 0, hc = 0; + for (e = t.first; e != null; e = e.next) { + int h = e.hash; + Object k = e.key; V v = e.val; + if ((h & n) == 0) { + ++lc; + lt.putTreeNode(h, k, v); + } + else { + ++hc; + ht.putTreeNode(h, k, v); + } + } + if (lc < TREE_THRESHOLD) { // throw away + for (p = lt.first; p != null; p = p.next) + ln = new Node(p.hash, p.key, + p.val, ln); + lt = null; + } + if (hc < TREE_THRESHOLD) { + for (p = ht.first; p != null; p = p.next) + hn = new Node(p.hash, p.key, + p.val, hn); + ht = null; + } + } + if (ln == null && lt != null) + ln = new Node(MOVED, lt, null, null); + if (hn == null && ht != null) + hn = new Node(MOVED, ht, null, null); + } + setTabAt(nextTab, i, ln); + setTabAt(nextTab, i + n, hn); + setTabAt(tab, i, fwd); + advance = true; } - else if (key.equals(e.key)) - retries = 0; - else - e = e.next; - } - else if (++retries > MAX_SCAN_RETRIES) { - lock(); - break; - } - else if ((retries & 1) == 0 && - (f = entryForHash(this, hash)) != first) { - e = first = f; // re-traverse if entry changed - retries = -1; + } finally { + t.unlockWrite(stamp); } } - return node; + else + advance = true; // already processed + } + } + + /* ---------------- Counter support -------------- */ + + final long sumCount() { + Cell[] as = counterCells; Cell a; + long sum = baseCount; + if (as != null) { + for (int i = 0; i < as.length; ++i) { + if ((a = as[i]) != null) + sum += a.value; + } + } + return sum; + } + + // See LongAdder version for explanation + private final void fullAddCount(long x, boolean wasUncontended) { + int h; + if ((h = ThreadLocalRandom.getProbe()) == 0) { + ThreadLocalRandom.localInit(); // force initialization + h = ThreadLocalRandom.getProbe(); + wasUncontended = true; } - - /** - * Scans for a node containing the given key while trying to - * acquire lock for a remove or replace operation. Upon - * return, guarantees that lock is held. Note that we must - * lock even if the key is not found, to ensure sequential - * consistency of updates. - */ - private void scanAndLock(Object key, int hash) { - // similar to but simpler than scanAndLockForPut - HashEntry first = entryForHash(this, hash); - HashEntry e = first; - int retries = -1; - while (!tryLock()) { - HashEntry f; - if (retries < 0) { - if (e == null || key.equals(e.key)) - retries = 0; - else - e = e.next; + boolean collide = false; // True if last slot nonempty + for (;;) { + Cell[] as; Cell a; int n; long v; + if ((as = counterCells) != null && (n = as.length) > 0) { + if ((a = as[(n - 1) & h]) == null) { + if (cellsBusy == 0) { // Try to attach new Cell + Cell r = new Cell(x); // Optimistic create + if (cellsBusy == 0 && + U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { + boolean created = false; + try { // Recheck under lock + Cell[] rs; int m, j; + if ((rs = counterCells) != null && + (m = rs.length) > 0 && + rs[j = (m - 1) & h] == null) { + rs[j] = r; + created = true; + } + } finally { + cellsBusy = 0; + } + if (created) + break; + continue; // Slot is now non-empty + } + } + collide = false; + } + else if (!wasUncontended) // CAS already known to fail + wasUncontended = true; // Continue after rehash + else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x)) + break; + else if (counterCells != as || n >= NCPU) + collide = false; // At max size or stale + else if (!collide) + collide = true; + else if (cellsBusy == 0 && + U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { + try { + if (counterCells == as) {// Expand table unless stale + Cell[] rs = new Cell[n << 1]; + for (int i = 0; i < n; ++i) + rs[i] = as[i]; + counterCells = rs; + } + } finally { + cellsBusy = 0; + } + collide = false; + continue; // Retry with expanded table } - else if (++retries > MAX_SCAN_RETRIES) { - lock(); - break; + h = ThreadLocalRandom.advanceProbe(h); + } + else if (cellsBusy == 0 && counterCells == as && + U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { + boolean init = false; + try { // Initialize table + if (counterCells == as) { + Cell[] rs = new Cell[2]; + rs[h & 1] = new Cell(x); + counterCells = rs; + init = true; + } + } finally { + cellsBusy = 0; } - else if ((retries & 1) == 0 && - (f = entryForHash(this, hash)) != first) { - e = first = f; - retries = -1; - } + if (init) + break; } + else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x)) + break; // Fall back on using base + } + } + + /* ----------------Table Traversal -------------- */ + + /** + * Encapsulates traversal for methods such as containsValue; also + * serves as a base class for other iterators and spliterators. + * + * Method advance visits once each still-valid node that was + * reachable upon iterator construction. It might miss some that + * were added to a bin after the bin was visited, which is OK wrt + * consistency guarantees. Maintaining this property in the face + * of possible ongoing resizes requires a fair amount of + * bookkeeping state that is difficult to optimize away amidst + * volatile accesses. Even so, traversal maintains reasonable + * throughput. + * + * Normally, iteration proceeds bin-by-bin traversing lists. + * However, if the table has been resized, then all future steps + * must traverse both the bin at the current index as well as at + * (index + baseSize); and so on for further resizings. To + * paranoically cope with potential sharing by users of iterators + * across threads, iteration terminates if a bounds checks fails + * for a table read. + */ + static class Traverser { + Node[] tab; // current table; updated if resized + Node next; // the next entry to use + int index; // index of bin to use next + int baseIndex; // current index of initial table + int baseLimit; // index bound for initial table + final int baseSize; // initial table size + + Traverser(Node[] tab, int size, int index, int limit) { + this.tab = tab; + this.baseSize = size; + this.baseIndex = this.index = index; + this.baseLimit = limit; + this.next = null; } /** - * Remove; match on key only if value null, else match both. + * Advances if possible, returning next valid node, or null if none. */ - final V remove(Object key, int hash, Object value) { - if (!tryLock()) - scanAndLock(key, hash); - V oldValue = null; - try { - HashEntry[] tab = table; - int index = (tab.length - 1) & hash; - HashEntry e = entryAt(tab, index); - HashEntry pred = null; - while (e != null) { - K k; - HashEntry next = e.next; - if ((k = e.key) == key || - (e.hash == hash && key.equals(k))) { - V v = e.value; - if (value == null || value == v || value.equals(v)) { - if (pred == null) - setEntryAt(tab, index, next); - else - pred.setNext(next); - ++modCount; - --count; - oldValue = v; - } - break; - } - pred = e; - e = next; - } - } finally { - unlock(); - } - return oldValue; - } - - final boolean replace(K key, int hash, V oldValue, V newValue) { - if (!tryLock()) - scanAndLock(key, hash); - boolean replaced = false; - try { - HashEntry e; - for (e = entryForHash(this, hash); e != null; e = e.next) { - K k; - if ((k = e.key) == key || - (e.hash == hash && key.equals(k))) { - if (oldValue.equals(e.value)) { - e.value = newValue; - ++modCount; - replaced = true; - } - break; + final Node advance() { + Node e; + if ((e = next) != null) + e = e.next; + for (;;) { + Node[] t; int i, n; Object ek; // must use locals in checks + if (e != null) + return next = e; + if (baseIndex >= baseLimit || (t = tab) == null || + (n = t.length) <= (i = index) || i < 0) + return next = null; + if ((e = tabAt(t, index)) != null && e.hash < 0) { + if ((ek = e.key) instanceof TreeBin) + e = ((TreeBin)ek).first; + else { + tab = (Node[])ek; + e = null; + continue; } } - } finally { - unlock(); - } - return replaced; - } - - final V replace(K key, int hash, V value) { - if (!tryLock()) - scanAndLock(key, hash); - V oldValue = null; - try { - HashEntry e; - for (e = entryForHash(this, hash); e != null; e = e.next) { - K k; - if ((k = e.key) == key || - (e.hash == hash && key.equals(k))) { - oldValue = e.value; - e.value = value; - ++modCount; - break; - } - } - } finally { - unlock(); - } - return oldValue; - } - - final void clear() { - lock(); - try { - HashEntry[] tab = table; - for (int i = 0; i < tab.length ; i++) - setEntryAt(tab, i, null); - ++modCount; - count = 0; - } finally { - unlock(); + if ((index += baseSize) >= n) + index = ++baseIndex; // visit upper slots if present } } } - // Accessing segments - /** - * Gets the jth element of given segment array (if nonnull) with - * volatile element access semantics via Unsafe. (The null check - * can trigger harmlessly only during deserialization.) Note: - * because each element of segments array is set only once (using - * fully ordered writes), some performance-sensitive methods rely - * on this method only as a recheck upon null reads. - */ - @SuppressWarnings("unchecked") - static final Segment segmentAt(Segment[] ss, int j) { - long u = (j << SSHIFT) + SBASE; - return ss == null ? null : - (Segment) UNSAFE.getObjectVolatile(ss, u); - } - - /** - * Returns the segment for the given index, creating it and - * recording in segment table (via CAS) if not already present. - * - * @param k the index - * @return the segment + * Base of key, value, and entry Iterators. Adds fields to + * Traverser to support iterator.remove */ - @SuppressWarnings("unchecked") - private Segment ensureSegment(int k) { - final Segment[] ss = this.segments; - long u = (k << SSHIFT) + SBASE; // raw offset - Segment seg; - if ((seg = (Segment)UNSAFE.getObjectVolatile(ss, u)) == null) { - Segment proto = ss[0]; // use segment 0 as prototype - int cap = proto.table.length; - float lf = proto.loadFactor; - int threshold = (int)(cap * lf); - HashEntry[] tab = (HashEntry[])new HashEntry[cap]; - if ((seg = (Segment)UNSAFE.getObjectVolatile(ss, u)) - == null) { // recheck - Segment s = new Segment(lf, threshold, tab); - while ((seg = (Segment)UNSAFE.getObjectVolatile(ss, u)) - == null) { - if (UNSAFE.compareAndSwapObject(ss, u, null, seg = s)) - break; - } - } + static class BaseIterator extends Traverser { + final ConcurrentHashMap map; + Node lastReturned; + BaseIterator(Node[] tab, int size, int index, int limit, + ConcurrentHashMap map) { + super(tab, size, index, limit); + this.map = map; + advance(); + } + + public final boolean hasNext() { return next != null; } + public final boolean hasMoreElements() { return next != null; } + + public final void remove() { + Node p; + if ((p = lastReturned) == null) + throw new IllegalStateException(); + lastReturned = null; + map.internalReplace((K)p.key, null, null); + } + } + + static final class KeyIterator extends BaseIterator + implements Iterator, Enumeration { + KeyIterator(Node[] tab, int index, int size, int limit, + ConcurrentHashMap map) { + super(tab, index, size, limit, map); + } + + public final K next() { + Node p; + if ((p = next) == null) + throw new NoSuchElementException(); + K k = (K)p.key; + lastReturned = p; + advance(); + return k; } - return seg; + + public final K nextElement() { return next(); } + } + + static final class ValueIterator extends BaseIterator + implements Iterator, Enumeration { + ValueIterator(Node[] tab, int index, int size, int limit, + ConcurrentHashMap map) { + super(tab, index, size, limit, map); + } + + public final V next() { + Node p; + if ((p = next) == null) + throw new NoSuchElementException(); + V v = p.val; + lastReturned = p; + advance(); + return v; + } + + public final V nextElement() { return next(); } + } + + static final class EntryIterator extends BaseIterator + implements Iterator> { + EntryIterator(Node[] tab, int index, int size, int limit, + ConcurrentHashMap map) { + super(tab, index, size, limit, map); + } + + public final Map.Entry next() { + Node p; + if ((p = next) == null) + throw new NoSuchElementException(); + K k = (K)p.key; + V v = p.val; + lastReturned = p; + advance(); + return new MapEntry(k, v, map); + } } - // Hash-based segment and entry accesses - - /** - * Gets the segment for the given hash code. - */ - @SuppressWarnings("unchecked") - private Segment segmentForHash(int h) { - long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE; - return (Segment) UNSAFE.getObjectVolatile(segments, u); + static final class KeySpliterator extends Traverser + implements Spliterator { + long est; // size estimate + KeySpliterator(Node[] tab, int size, int index, int limit, + long est) { + super(tab, size, index, limit); + this.est = est; + } + + public Spliterator trySplit() { + int i, f, h; + return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : + new KeySpliterator(tab, baseSize, baseLimit = h, + f, est >>>= 1); + } + + public void forEachRemaining(Consumer action) { + if (action == null) throw new NullPointerException(); + for (Node p; (p = advance()) != null;) + action.accept((K)p.key); + } + + public boolean tryAdvance(Consumer action) { + if (action == null) throw new NullPointerException(); + Node p; + if ((p = advance()) == null) + return false; + action.accept((K)p.key); + return true; + } + + public long estimateSize() { return est; } + + public int characteristics() { + return Spliterator.DISTINCT | Spliterator.CONCURRENT | + Spliterator.NONNULL; + } } - /** - * Gets the table entry for the given segment and hash code. - */ - @SuppressWarnings("unchecked") - static final HashEntry entryForHash(Segment seg, int h) { - HashEntry[] tab; - return (seg == null || (tab = seg.table) == null) ? null : - (HashEntry) UNSAFE.getObjectVolatile - (tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE); + static final class ValueSpliterator extends Traverser + implements Spliterator { + long est; // size estimate + ValueSpliterator(Node[] tab, int size, int index, int limit, + long est) { + super(tab, size, index, limit); + this.est = est; + } + + public Spliterator trySplit() { + int i, f, h; + return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : + new ValueSpliterator(tab, baseSize, baseLimit = h, + f, est >>>= 1); + } + + public void forEachRemaining(Consumer action) { + if (action == null) throw new NullPointerException(); + for (Node p; (p = advance()) != null;) + action.accept(p.val); + } + + public boolean tryAdvance(Consumer action) { + if (action == null) throw new NullPointerException(); + Node p; + if ((p = advance()) == null) + return false; + action.accept(p.val); + return true; + } + + public long estimateSize() { return est; } + + public int characteristics() { + return Spliterator.CONCURRENT | Spliterator.NONNULL; + } } + static final class EntrySpliterator extends Traverser + implements Spliterator> { + final ConcurrentHashMap map; // To export MapEntry + long est; // size estimate + EntrySpliterator(Node[] tab, int size, int index, int limit, + long est, ConcurrentHashMap map) { + super(tab, size, index, limit); + this.map = map; + this.est = est; + } + + public Spliterator> trySplit() { + int i, f, h; + return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : + new EntrySpliterator(tab, baseSize, baseLimit = h, + f, est >>>= 1, map); + } + + public void forEachRemaining(Consumer> action) { + if (action == null) throw new NullPointerException(); + for (Node p; (p = advance()) != null; ) + action.accept(new MapEntry((K)p.key, p.val, map)); + } + + public boolean tryAdvance(Consumer> action) { + if (action == null) throw new NullPointerException(); + Node p; + if ((p = advance()) == null) + return false; + action.accept(new MapEntry((K)p.key, p.val, map)); + return true; + } + + public long estimateSize() { return est; } + + public int characteristics() { + return Spliterator.DISTINCT | Spliterator.CONCURRENT | + Spliterator.NONNULL; + } + } + + /* ---------------- Public operations -------------- */ /** - * Creates a new, empty map with the specified initial - * capacity, load factor and concurrency level. - * - * @param initialCapacity the initial capacity. The implementation - * performs internal sizing to accommodate this many elements. - * @param loadFactor the load factor threshold, used to control resizing. - * Resizing may be performed when the average number of elements per - * bin exceeds this threshold. - * @param concurrencyLevel the estimated number of concurrently - * updating threads. The implementation performs internal sizing - * to try to accommodate this many threads. - * @throws IllegalArgumentException if the initial capacity is - * negative or the load factor or concurrencyLevel are - * nonpositive. + * Creates a new, empty map with the default initial table size (16). */ - @SuppressWarnings("unchecked") - public ConcurrentHashMap(int initialCapacity, - float loadFactor, int concurrencyLevel) { - if (!(loadFactor > 0) || initialCapacity < 0 || concurrencyLevel <= 0) - throw new IllegalArgumentException(); - if (concurrencyLevel > MAX_SEGMENTS) - concurrencyLevel = MAX_SEGMENTS; - // Find power-of-two sizes best matching arguments - int sshift = 0; - int ssize = 1; - while (ssize < concurrencyLevel) { - ++sshift; - ssize <<= 1; - } - this.segmentShift = 32 - sshift; - this.segmentMask = ssize - 1; - if (initialCapacity > MAXIMUM_CAPACITY) - initialCapacity = MAXIMUM_CAPACITY; - int c = initialCapacity / ssize; - if (c * ssize < initialCapacity) - ++c; - int cap = MIN_SEGMENT_TABLE_CAPACITY; - while (cap < c) - cap <<= 1; - // create segments and segments[0] - Segment s0 = - new Segment(loadFactor, (int)(cap * loadFactor), - (HashEntry[])new HashEntry[cap]); - Segment[] ss = (Segment[])new Segment[ssize]; - UNSAFE.putOrderedObject(ss, SBASE, s0); // ordered write of segments[0] - this.segments = ss; + public ConcurrentHashMap() { } /** - * Creates a new, empty map with the specified initial capacity - * and load factor and with the default concurrencyLevel (16). + * Creates a new, empty map with an initial table size + * accommodating the specified number of elements without the need + * to dynamically resize. * * @param initialCapacity The implementation performs internal * sizing to accommodate this many elements. - * @param loadFactor the load factor threshold, used to control resizing. - * Resizing may be performed when the average number of elements per - * bin exceeds this threshold. + * @throws IllegalArgumentException if the initial capacity of + * elements is negative + */ + public ConcurrentHashMap(int initialCapacity) { + if (initialCapacity < 0) + throw new IllegalArgumentException(); + int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ? + MAXIMUM_CAPACITY : + tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1)); + this.sizeCtl = cap; + } + + /** + * Creates a new map with the same mappings as the given map. + * + * @param m the map + */ + public ConcurrentHashMap(Map m) { + this.sizeCtl = DEFAULT_CAPACITY; + internalPutAll(m); + } + + /** + * Creates a new, empty map with an initial table size based on + * the given number of elements ({@code initialCapacity}) and + * initial table density ({@code loadFactor}). + * + * @param initialCapacity the initial capacity. The implementation + * performs internal sizing to accommodate this many elements, + * given the specified load factor. + * @param loadFactor the load factor (table density) for + * establishing the initial table size * @throws IllegalArgumentException if the initial capacity of * elements is negative or the load factor is nonpositive * * @since 1.6 */ public ConcurrentHashMap(int initialCapacity, float loadFactor) { - this(initialCapacity, loadFactor, DEFAULT_CONCURRENCY_LEVEL); - } - - /** - * Creates a new, empty map with the specified initial capacity, - * and with default load factor (0.75) and concurrencyLevel (16). - * - * @param initialCapacity the initial capacity. The implementation - * performs internal sizing to accommodate this many elements. - * @throws IllegalArgumentException if the initial capacity of - * elements is negative. - */ - public ConcurrentHashMap(int initialCapacity) { - this(initialCapacity, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL); + this(initialCapacity, loadFactor, 1); } /** - * Creates a new, empty map with a default initial capacity (16), - * load factor (0.75) and concurrencyLevel (16). + * Creates a new, empty map with an initial table size based on + * the given number of elements ({@code initialCapacity}), table + * density ({@code loadFactor}), and number of concurrently + * updating threads ({@code concurrencyLevel}). + * + * @param initialCapacity the initial capacity. The implementation + * performs internal sizing to accommodate this many elements, + * given the specified load factor. + * @param loadFactor the load factor (table density) for + * establishing the initial table size + * @param concurrencyLevel the estimated number of concurrently + * updating threads. The implementation may use this value as + * a sizing hint. + * @throws IllegalArgumentException if the initial capacity is + * negative or the load factor or concurrencyLevel are + * nonpositive */ - public ConcurrentHashMap() { - this(DEFAULT_INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL); + public ConcurrentHashMap(int initialCapacity, + float loadFactor, int concurrencyLevel) { + if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0) + throw new IllegalArgumentException(); + if (initialCapacity < concurrencyLevel) // Use at least as many bins + initialCapacity = concurrencyLevel; // as estimated threads + long size = (long)(1.0 + (long)initialCapacity / loadFactor); + int cap = (size >= (long)MAXIMUM_CAPACITY) ? + MAXIMUM_CAPACITY : tableSizeFor((int)size); + this.sizeCtl = cap; } /** - * Creates a new map with the same mappings as the given map. - * The map is created with a capacity of 1.5 times the number - * of mappings in the given map or 16 (whichever is greater), - * and a default load factor (0.75) and concurrencyLevel (16). + * Creates a new {@link Set} backed by a ConcurrentHashMap + * from the given type to {@code Boolean.TRUE}. * - * @param m the map + * @return the new set */ - public ConcurrentHashMap(Map m) { - this(Math.max((int) (m.size() / DEFAULT_LOAD_FACTOR) + 1, - DEFAULT_INITIAL_CAPACITY), - DEFAULT_LOAD_FACTOR, DEFAULT_CONCURRENCY_LEVEL); - putAll(m); + public static KeySetView newKeySet() { + return new KeySetView + (new ConcurrentHashMap(), Boolean.TRUE); + } + + /** + * Creates a new {@link Set} backed by a ConcurrentHashMap + * from the given type to {@code Boolean.TRUE}. + * + * @param initialCapacity The implementation performs internal + * sizing to accommodate this many elements. + * @throws IllegalArgumentException if the initial capacity of + * elements is negative + * @return the new set + */ + public static KeySetView newKeySet(int initialCapacity) { + return new KeySetView + (new ConcurrentHashMap(initialCapacity), Boolean.TRUE); } /** @@ -834,38 +2637,7 @@ * @return {@code true} if this map contains no key-value mappings */ public boolean isEmpty() { - /* - * Sum per-segment modCounts to avoid mis-reporting when - * elements are concurrently added and removed in one segment - * while checking another, in which case the table was never - * actually empty at any point. (The sum ensures accuracy up - * through at least 1<<31 per-segment modifications before - * recheck.) Methods size() and containsValue() use similar - * constructions for stability checks. - */ - long sum = 0L; - final Segment[] segments = this.segments; - for (int j = 0; j < segments.length; ++j) { - Segment seg = segmentAt(segments, j); - if (seg != null) { - if (seg.count != 0) - return false; - sum += seg.modCount; - } - } - if (sum != 0L) { // recheck unless no modifications - for (int j = 0; j < segments.length; ++j) { - Segment seg = segmentAt(segments, j); - if (seg != null) { - if (seg.count != 0) - return false; - sum -= seg.modCount; - } - } - if (sum != 0L) - return false; - } - return true; + return sumCount() <= 0L; // ignore transient negative values } /** @@ -876,43 +2648,24 @@ * @return the number of key-value mappings in this map */ public int size() { - // Try a few times to get accurate count. On failure due to - // continuous async changes in table, resort to locking. - final Segment[] segments = this.segments; - int size; - boolean overflow; // true if size overflows 32 bits - long sum; // sum of modCounts - long last = 0L; // previous sum - int retries = -1; // first iteration isn't retry - try { - for (;;) { - if (retries++ == RETRIES_BEFORE_LOCK) { - for (int j = 0; j < segments.length; ++j) - ensureSegment(j).lock(); // force creation - } - sum = 0L; - size = 0; - overflow = false; - for (int j = 0; j < segments.length; ++j) { - Segment seg = segmentAt(segments, j); - if (seg != null) { - sum += seg.modCount; - int c = seg.count; - if (c < 0 || (size += c) < 0) - overflow = true; - } - } - if (sum == last) - break; - last = sum; - } - } finally { - if (retries > RETRIES_BEFORE_LOCK) { - for (int j = 0; j < segments.length; ++j) - segmentAt(segments, j).unlock(); - } - } - return overflow ? Integer.MAX_VALUE : size; + long n = sumCount(); + return ((n < 0L) ? 0 : + (n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE : + (int)n); + } + + /** + * Returns the number of mappings. This method should be used + * instead of {@link #size} because a ConcurrentHashMap may + * contain more mappings than can be represented as an int. The + * value returned is an estimate; the actual count may differ if + * there are concurrent insertions or removals. + * + * @return the number of mappings + */ + public long mappingCount() { + long n = sumCount(); + return (n < 0L) ? 0L : n; // ignore transient negative values } /** @@ -926,23 +2679,24 @@ * * @throws NullPointerException if the specified key is null */ - @SuppressWarnings("unchecked") public V get(Object key) { - Segment s; // manually integrate access methods to reduce overhead - HashEntry[] tab; - int h = hash(key); - long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE; - if ((s = (Segment)UNSAFE.getObjectVolatile(segments, u)) != null && - (tab = s.table) != null) { - for (HashEntry e = (HashEntry) UNSAFE.getObjectVolatile - (tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE); - e != null; e = e.next) { - K k; - if ((k = e.key) == key || (e.hash == h && key.equals(k))) - return e.value; - } - } - return null; + return internalGet(key); + } + + /** + * Returns the value to which the specified key is mapped, or the + * given default value if this map contains no mapping for the + * key. + * + * @param key the key whose associated value is to be returned + * @param defaultValue the value to return if this map contains + * no mapping for the given key + * @return the mapping for the key, if present; else the default value + * @throws NullPointerException if the specified key is null + */ + public V getOrDefault(Object key, V defaultValue) { + V v; + return (v = internalGet(key)) == null ? defaultValue : v; } /** @@ -954,29 +2708,14 @@ * {@code equals} method; {@code false} otherwise * @throws NullPointerException if the specified key is null */ - @SuppressWarnings("unchecked") public boolean containsKey(Object key) { - Segment s; // same as get() except no need for volatile value read - HashEntry[] tab; - int h = hash(key); - long u = (((h >>> segmentShift) & segmentMask) << SSHIFT) + SBASE; - if ((s = (Segment)UNSAFE.getObjectVolatile(segments, u)) != null && - (tab = s.table) != null) { - for (HashEntry e = (HashEntry) UNSAFE.getObjectVolatile - (tab, ((long)(((tab.length - 1) & h)) << TSHIFT) + TBASE); - e != null; e = e.next) { - K k; - if ((k = e.key) == key || (e.hash == h && key.equals(k))) - return true; - } - } - return false; + return internalGet(key) != null; } /** * Returns {@code true} if this map maps one or more keys to the - * specified value. Note: This method requires a full traversal - * of the map, and so is much slower than method {@code containsKey}. + * specified value. Note: This method may require a full traversal + * of the map, and is much slower than method {@code containsKey}. * * @param value value whose presence in this map is to be tested * @return {@code true} if this map maps one or more keys to the @@ -984,49 +2723,18 @@ * @throws NullPointerException if the specified value is null */ public boolean containsValue(Object value) { - // Same idea as size() if (value == null) throw new NullPointerException(); - final Segment[] segments = this.segments; - boolean found = false; - long last = 0; - int retries = -1; - try { - outer: for (;;) { - if (retries++ == RETRIES_BEFORE_LOCK) { - for (int j = 0; j < segments.length; ++j) - ensureSegment(j).lock(); // force creation - } - long hashSum = 0L; - int sum = 0; - for (int j = 0; j < segments.length; ++j) { - HashEntry[] tab; - Segment seg = segmentAt(segments, j); - if (seg != null && (tab = seg.table) != null) { - for (int i = 0 ; i < tab.length; i++) { - HashEntry e; - for (e = entryAt(tab, i); e != null; e = e.next) { - V v = e.value; - if (v != null && value.equals(v)) { - found = true; - break outer; - } - } - } - sum += seg.modCount; - } - } - if (retries > 0 && sum == last) - break; - last = sum; - } - } finally { - if (retries > RETRIES_BEFORE_LOCK) { - for (int j = 0; j < segments.length; ++j) - segmentAt(segments, j).unlock(); + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + V v; + if ((v = p.val) == value || value.equals(v)) + return true; } } - return found; + return false; } /** @@ -1061,17 +2769,8 @@ * {@code null} if there was no mapping for {@code key} * @throws NullPointerException if the specified key or value is null */ - @SuppressWarnings("unchecked") public V put(K key, V value) { - Segment s; - if (value == null) - throw new NullPointerException(); - int hash = hash(key); - int j = (hash >>> segmentShift) & segmentMask; - if ((s = (Segment)UNSAFE.getObject // nonvolatile; recheck - (segments, (j << SSHIFT) + SBASE)) == null) // in ensureSegment - s = ensureSegment(j); - return s.put(key, hash, value, false); + return internalPut(key, value, false); } /** @@ -1081,17 +2780,8 @@ * or {@code null} if there was no mapping for the key * @throws NullPointerException if the specified key or value is null */ - @SuppressWarnings("unchecked") public V putIfAbsent(K key, V value) { - Segment s; - if (value == null) - throw new NullPointerException(); - int hash = hash(key); - int j = (hash >>> segmentShift) & segmentMask; - if ((s = (Segment)UNSAFE.getObject - (segments, (j << SSHIFT) + SBASE)) == null) - s = ensureSegment(j); - return s.put(key, hash, value, true); + return internalPut(key, value, true); } /** @@ -1102,8 +2792,105 @@ * @param m mappings to be stored in this map */ public void putAll(Map m) { - for (Map.Entry e : m.entrySet()) - put(e.getKey(), e.getValue()); + internalPutAll(m); + } + + /** + * If the specified key is not already associated with a value, + * attempts to compute its value using the given mapping function + * and enters it into this map unless {@code null}. The entire + * method invocation is performed atomically, so the function is + * applied at most once per key. Some attempted update operations + * on this map by other threads may be blocked while computation + * is in progress, so the computation should be short and simple, + * and must not attempt to update any other mappings of this map. + * + * @param key key with which the specified value is to be associated + * @param mappingFunction the function to compute a value + * @return the current (existing or computed) value associated with + * the specified key, or null if the computed value is null + * @throws NullPointerException if the specified key or mappingFunction + * is null + * @throws IllegalStateException if the computation detectably + * attempts a recursive update to this map that would + * otherwise never complete + * @throws RuntimeException or Error if the mappingFunction does so, + * in which case the mapping is left unestablished + */ + public V computeIfAbsent(K key, Function mappingFunction) { + return internalComputeIfAbsent(key, mappingFunction); + } + + /** + * If the value for the specified key is present, attempts to + * compute a new mapping given the key and its current mapped + * value. The entire method invocation is performed atomically. + * Some attempted update operations on this map by other threads + * may be blocked while computation is in progress, so the + * computation should be short and simple, and must not attempt to + * update any other mappings of this map. + * + * @param key key with which a value may be associated + * @param remappingFunction the function to compute a value + * @return the new value associated with the specified key, or null if none + * @throws NullPointerException if the specified key or remappingFunction + * is null + * @throws IllegalStateException if the computation detectably + * attempts a recursive update to this map that would + * otherwise never complete + * @throws RuntimeException or Error if the remappingFunction does so, + * in which case the mapping is unchanged + */ + public V computeIfPresent(K key, BiFunction remappingFunction) { + return internalCompute(key, true, remappingFunction); + } + + /** + * Attempts to compute a mapping for the specified key and its + * current mapped value (or {@code null} if there is no current + * mapping). The entire method invocation is performed atomically. + * Some attempted update operations on this map by other threads + * may be blocked while computation is in progress, so the + * computation should be short and simple, and must not attempt to + * update any other mappings of this Map. + * + * @param key key with which the specified value is to be associated + * @param remappingFunction the function to compute a value + * @return the new value associated with the specified key, or null if none + * @throws NullPointerException if the specified key or remappingFunction + * is null + * @throws IllegalStateException if the computation detectably + * attempts a recursive update to this map that would + * otherwise never complete + * @throws RuntimeException or Error if the remappingFunction does so, + * in which case the mapping is unchanged + */ + public V compute(K key, BiFunction remappingFunction) { + return internalCompute(key, false, remappingFunction); + } + + /** + * If the specified key is not already associated with a + * (non-null) value, associates it with the given value. + * Otherwise, replaces the value with the results of the given + * remapping function, or removes if {@code null}. The entire + * method invocation is performed atomically. Some attempted + * update operations on this map by other threads may be blocked + * while computation is in progress, so the computation should be + * short and simple, and must not attempt to update any other + * mappings of this Map. + * + * @param key key with which the specified value is to be associated + * @param value the value to use if absent + * @param remappingFunction the function to recompute a value if present + * @return the new value associated with the specified key, or null if none + * @throws NullPointerException if the specified key or the + * remappingFunction is null + * @throws RuntimeException or Error if the remappingFunction does so, + * in which case the mapping is unchanged + */ + public V merge(K key, V value, BiFunction remappingFunction) { + return internalMerge(key, value, remappingFunction); } /** @@ -1116,9 +2903,7 @@ * @throws NullPointerException if the specified key is null */ public V remove(Object key) { - int hash = hash(key); - Segment s = segmentForHash(hash); - return s == null ? null : s.remove(key, hash, null); + return internalReplace(key, null, null); } /** @@ -1127,10 +2912,9 @@ * @throws NullPointerException if the specified key is null */ public boolean remove(Object key, Object value) { - int hash = hash(key); - Segment s; - return value != null && (s = segmentForHash(hash)) != null && - s.remove(key, hash, value) != null; + if (key == null) + throw new NullPointerException(); + return value != null && internalReplace(key, null, value) != null; } /** @@ -1139,11 +2923,9 @@ * @throws NullPointerException if any of the arguments are null */ public boolean replace(K key, V oldValue, V newValue) { - int hash = hash(key); - if (oldValue == null || newValue == null) + if (key == null || oldValue == null || newValue == null) throw new NullPointerException(); - Segment s = segmentForHash(hash); - return s != null && s.replace(key, hash, oldValue, newValue); + return internalReplace(key, newValue, oldValue) != null; } /** @@ -1154,23 +2936,16 @@ * @throws NullPointerException if the specified key or value is null */ public V replace(K key, V value) { - int hash = hash(key); - if (value == null) + if (key == null || value == null) throw new NullPointerException(); - Segment s = segmentForHash(hash); - return s == null ? null : s.replace(key, hash, value); + return internalReplace(key, value, null); } /** * Removes all of the mappings from this map. */ public void clear() { - final Segment[] segments = this.segments; - for (int j = 0; j < segments.length; ++j) { - Segment s = segmentAt(segments, j); - if (s != null) - s.clear(); - } + internalClear(); } /** @@ -1188,10 +2963,29 @@ * and guarantees to traverse elements as they existed upon * construction of the iterator, and may (but is not guaranteed to) * reflect any modifications subsequent to construction. + * + * @return the set view */ - public Set keySet() { - Set ks = keySet; - return (ks != null) ? ks : (keySet = new KeySet()); + public KeySetView keySet() { + KeySetView ks = keySet; + return (ks != null) ? ks : (keySet = new KeySetView(this, null)); + } + + /** + * Returns a {@link Set} view of the keys in this map, using the + * given common mapped value for any additions (i.e., {@link + * Collection#add} and {@link Collection#addAll(Collection)}). + * This is of course only appropriate if it is acceptable to use + * the same value for all additions from this view. + * + * @param mappedValue the mapped value to use for any additions + * @return the set view + * @throws NullPointerException if the mappedValue is null + */ + public KeySetView keySet(V mappedValue) { + if (mappedValue == null) + throw new NullPointerException(); + return new KeySetView(this, mappedValue); } /** @@ -1209,10 +3003,12 @@ * and guarantees to traverse elements as they existed upon * construction of the iterator, and may (but is not guaranteed to) * reflect any modifications subsequent to construction. + * + * @return the collection view */ public Collection values() { - Collection vs = values; - return (vs != null) ? vs : (values = new Values()); + ValuesView vs = values; + return (vs != null) ? vs : (values = new ValuesView(this)); } /** @@ -1222,18 +3018,19 @@ * removal, which removes the corresponding mapping from the map, * via the {@code Iterator.remove}, {@code Set.remove}, * {@code removeAll}, {@code retainAll}, and {@code clear} - * operations. It does not support the {@code add} or - * {@code addAll} operations. + * operations. * *

The view's {@code iterator} is a "weakly consistent" iterator * that will never throw {@link ConcurrentModificationException}, * and guarantees to traverse elements as they existed upon * construction of the iterator, and may (but is not guaranteed to) * reflect any modifications subsequent to construction. + * + * @return the set view */ public Set> entrySet() { - Set> es = entrySet; - return (es != null) ? es : (entrySet = new EntrySet()); + EntrySetView es = entrySet; + return (es != null) ? es : (entrySet = new EntrySetView(this)); } /** @@ -1243,7 +3040,9 @@ * @see #keySet() */ public Enumeration keys() { - return new KeyIterator(); + Node[] t; + int f = (t = table) == null ? 0 : t.length; + return new KeyIterator(t, f, 0, f, this); } /** @@ -1253,192 +3052,111 @@ * @see #values() */ public Enumeration elements() { - return new ValueIterator(); + Node[] t; + int f = (t = table) == null ? 0 : t.length; + return new ValueIterator(t, f, 0, f, this); } - /* ---------------- Iterator Support -------------- */ - - abstract class HashIterator { - int nextSegmentIndex; - int nextTableIndex; - HashEntry[] currentTable; - HashEntry nextEntry; - HashEntry lastReturned; - - HashIterator() { - nextSegmentIndex = segments.length - 1; - nextTableIndex = -1; - advance(); + /** + * Returns the hash code value for this {@link Map}, i.e., + * the sum of, for each key-value pair in the map, + * {@code key.hashCode() ^ value.hashCode()}. + * + * @return the hash code value for this map + */ + public int hashCode() { + int h = 0; + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) + h += p.key.hashCode() ^ p.val.hashCode(); } - - /** - * Sets nextEntry to first node of next non-empty table - * (in backwards order, to simplify checks). - */ - final void advance() { - for (;;) { - if (nextTableIndex >= 0) { - if ((nextEntry = entryAt(currentTable, - nextTableIndex--)) != null) - break; - } - else if (nextSegmentIndex >= 0) { - Segment seg = segmentAt(segments, nextSegmentIndex--); - if (seg != null && (currentTable = seg.table) != null) - nextTableIndex = currentTable.length - 1; - } - else - break; - } - } - - final HashEntry nextEntry() { - HashEntry e = nextEntry; - if (e == null) - throw new NoSuchElementException(); - lastReturned = e; // cannot assign until after null check - if ((nextEntry = e.next) == null) - advance(); - return e; - } - - public final boolean hasNext() { return nextEntry != null; } - public final boolean hasMoreElements() { return nextEntry != null; } - - public final void remove() { - if (lastReturned == null) - throw new IllegalStateException(); - ConcurrentHashMap.this.remove(lastReturned.key); - lastReturned = null; - } - } - - final class KeyIterator - extends HashIterator - implements Iterator, Enumeration - { - public final K next() { return super.nextEntry().key; } - public final K nextElement() { return super.nextEntry().key; } - } - - final class ValueIterator - extends HashIterator - implements Iterator, Enumeration - { - public final V next() { return super.nextEntry().value; } - public final V nextElement() { return super.nextEntry().value; } + return h; } /** - * Custom Entry class used by EntryIterator.next(), that relays - * setValue changes to the underlying map. + * Returns a string representation of this map. The string + * representation consists of a list of key-value mappings (in no + * particular order) enclosed in braces ("{@code {}}"). Adjacent + * mappings are separated by the characters {@code ", "} (comma + * and space). Each key-value mapping is rendered as the key + * followed by an equals sign ("{@code =}") followed by the + * associated value. + * + * @return a string representation of this map */ - final class WriteThroughEntry - extends AbstractMap.SimpleEntry - { - static final long serialVersionUID = 7249069246763182397L; - - WriteThroughEntry(K k, V v) { - super(k,v); - } - - /** - * Sets our entry's value and writes through to the map. The - * value to return is somewhat arbitrary here. Since a - * WriteThroughEntry does not necessarily track asynchronous - * changes, the most recent "previous" value could be - * different from what we return (or could even have been - * removed in which case the put will re-establish). We do not - * and cannot guarantee more. - */ - public V setValue(V value) { - if (value == null) throw new NullPointerException(); - V v = super.setValue(value); - ConcurrentHashMap.this.put(getKey(), value); - return v; - } - } - - final class EntryIterator - extends HashIterator - implements Iterator> - { - public Map.Entry next() { - HashEntry e = super.nextEntry(); - return new WriteThroughEntry(e.key, e.value); - } - } - - final class KeySet extends AbstractSet { - public Iterator iterator() { - return new KeyIterator(); - } - public int size() { - return ConcurrentHashMap.this.size(); - } - public boolean isEmpty() { - return ConcurrentHashMap.this.isEmpty(); - } - public boolean contains(Object o) { - return ConcurrentHashMap.this.containsKey(o); + public String toString() { + Node[] t; + int f = (t = table) == null ? 0 : t.length; + Traverser it = new Traverser(t, f, 0, f); + StringBuilder sb = new StringBuilder(); + sb.append('{'); + Node p; + if ((p = it.advance()) != null) { + for (;;) { + K k = (K)p.key; + V v = p.val; + sb.append(k == this ? "(this Map)" : k); + sb.append('='); + sb.append(v == this ? "(this Map)" : v); + if ((p = it.advance()) == null) + break; + sb.append(',').append(' '); + } } - public boolean remove(Object o) { - return ConcurrentHashMap.this.remove(o) != null; - } - public void clear() { - ConcurrentHashMap.this.clear(); - } - } - - final class Values extends AbstractCollection { - public Iterator iterator() { - return new ValueIterator(); - } - public int size() { - return ConcurrentHashMap.this.size(); - } - public boolean isEmpty() { - return ConcurrentHashMap.this.isEmpty(); - } - public boolean contains(Object o) { - return ConcurrentHashMap.this.containsValue(o); - } - public void clear() { - ConcurrentHashMap.this.clear(); - } + return sb.append('}').toString(); } - final class EntrySet extends AbstractSet> { - public Iterator> iterator() { - return new EntryIterator(); - } - public boolean contains(Object o) { - if (!(o instanceof Map.Entry)) + /** + * Compares the specified object with this map for equality. + * Returns {@code true} if the given object is a map with the same + * mappings as this map. This operation may return misleading + * results if either map is concurrently modified during execution + * of this method. + * + * @param o object to be compared for equality with this map + * @return {@code true} if the specified object is equal to this map + */ + public boolean equals(Object o) { + if (o != this) { + if (!(o instanceof Map)) return false; - Map.Entry e = (Map.Entry)o; - V v = ConcurrentHashMap.this.get(e.getKey()); - return v != null && v.equals(e.getValue()); + Map m = (Map) o; + Node[] t; + int f = (t = table) == null ? 0 : t.length; + Traverser it = new Traverser(t, f, 0, f); + for (Node p; (p = it.advance()) != null; ) { + V val = p.val; + Object v = m.get(p.key); + if (v == null || (v != val && !v.equals(val))) + return false; + } + for (Map.Entry e : m.entrySet()) { + Object mk, mv, v; + if ((mk = e.getKey()) == null || + (mv = e.getValue()) == null || + (v = internalGet(mk)) == null || + (mv != v && !mv.equals(v))) + return false; + } } - public boolean remove(Object o) { - if (!(o instanceof Map.Entry)) - return false; - Map.Entry e = (Map.Entry)o; - return ConcurrentHashMap.this.remove(e.getKey(), e.getValue()); - } - public int size() { - return ConcurrentHashMap.this.size(); - } - public boolean isEmpty() { - return ConcurrentHashMap.this.isEmpty(); - } - public void clear() { - ConcurrentHashMap.this.clear(); - } + return true; } /* ---------------- Serialization Support -------------- */ /** + * Stripped-down version of helper class used in previous version, + * declared for the sake of serialization compatibility + */ + static class Segment extends ReentrantLock implements Serializable { + private static final long serialVersionUID = 2249069246763182397L; + final float loadFactor; + Segment(float lf) { this.loadFactor = lf; } + } + + /** * Saves the state of the {@code ConcurrentHashMap} instance to a * stream (i.e., serializes it). * @param s the stream @@ -1448,119 +3166,2701 @@ * The key-value mappings are emitted in no particular order. */ private void writeObject(java.io.ObjectOutputStream s) - throws java.io.IOException { - // force all segments for serialization compatibility - for (int k = 0; k < segments.length; ++k) - ensureSegment(k); - s.defaultWriteObject(); - - final Segment[] segments = this.segments; - for (int k = 0; k < segments.length; ++k) { - Segment seg = segmentAt(segments, k); - seg.lock(); - try { - HashEntry[] tab = seg.table; - for (int i = 0; i < tab.length; ++i) { - HashEntry e; - for (e = entryAt(tab, i); e != null; e = e.next) { - s.writeObject(e.key); - s.writeObject(e.value); - } - } - } finally { - seg.unlock(); + throws java.io.IOException { + // For serialization compatibility + // Emulate segment calculation from previous version of this class + int sshift = 0; + int ssize = 1; + while (ssize < DEFAULT_CONCURRENCY_LEVEL) { + ++sshift; + ssize <<= 1; + } + int segmentShift = 32 - sshift; + int segmentMask = ssize - 1; + Segment[] segments = (Segment[]) + new Segment[DEFAULT_CONCURRENCY_LEVEL]; + for (int i = 0; i < segments.length; ++i) + segments[i] = new Segment(LOAD_FACTOR); + s.putFields().put("segments", segments); + s.putFields().put("segmentShift", segmentShift); + s.putFields().put("segmentMask", segmentMask); + s.writeFields(); + + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + s.writeObject(p.key); + s.writeObject(p.val); } } s.writeObject(null); s.writeObject(null); + segments = null; // throw away } /** * Reconstitutes the instance from a stream (that is, deserializes it). * @param s the stream */ - @SuppressWarnings("unchecked") private void readObject(java.io.ObjectInputStream s) - throws java.io.IOException, ClassNotFoundException { - // Don't call defaultReadObject() - ObjectInputStream.GetField oisFields = s.readFields(); - final Segment[] oisSegments = (Segment[])oisFields.get("segments", null); - - final int ssize = oisSegments.length; - if (ssize < 1 || ssize > MAX_SEGMENTS - || (ssize & (ssize-1)) != 0 ) // ssize not power of two - throw new java.io.InvalidObjectException("Bad number of segments:" - + ssize); - int sshift = 0, ssizeTmp = ssize; - while (ssizeTmp > 1) { - ++sshift; - ssizeTmp >>>= 1; + throws java.io.IOException, ClassNotFoundException { + s.defaultReadObject(); + + // Create all nodes, then place in table once size is known + long size = 0L; + Node p = null; + for (;;) { + K k = (K) s.readObject(); + V v = (V) s.readObject(); + if (k != null && v != null) { + int h = spread(k.hashCode()); + p = new Node(h, k, v, p); + ++size; + } + else + break; + } + if (p != null) { + boolean init = false; + int n; + if (size >= (long)(MAXIMUM_CAPACITY >>> 1)) + n = MAXIMUM_CAPACITY; + else { + int sz = (int)size; + n = tableSizeFor(sz + (sz >>> 1) + 1); + } + int sc = sizeCtl; + boolean collide = false; + if (n > sc && + U.compareAndSwapInt(this, SIZECTL, sc, -1)) { + try { + if (table == null) { + init = true; + Node[] tab = (Node[])new Node[n]; + int mask = n - 1; + while (p != null) { + int j = p.hash & mask; + Node next = p.next; + Node q = p.next = tabAt(tab, j); + setTabAt(tab, j, p); + if (!collide && q != null && q.hash == p.hash) + collide = true; + p = next; + } + table = tab; + addCount(size, -1); + sc = n - (n >>> 2); + } + } finally { + sizeCtl = sc; + } + if (collide) { // rescan and convert to TreeBins + Node[] tab = table; + for (int i = 0; i < tab.length; ++i) { + int c = 0; + for (Node e = tabAt(tab, i); e != null; e = e.next) { + if (++c > TREE_THRESHOLD && + (e.key instanceof Comparable)) { + replaceWithTreeBin(tab, i, e.key); + break; + } + } + } + } + } + if (!init) { // Can only happen if unsafely published. + while (p != null) { + internalPut((K)p.key, p.val, false); + p = p.next; + } + } + } + } + + // ------------------------------------------------------- + + // Overrides of other default Map methods + + public void forEach(BiConsumer action) { + if (action == null) throw new NullPointerException(); + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + action.accept((K)p.key, p.val); + } + } + } + + public void replaceAll(BiFunction function) { + if (function == null) throw new NullPointerException(); + Node[] t; + if ((t = table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + K k = (K)p.key; + internalPut(k, function.apply(k, p.val), false); + } } - UNSAFE.putIntVolatile(this, SEGSHIFT_OFFSET, 32 - sshift); - UNSAFE.putIntVolatile(this, SEGMASK_OFFSET, ssize - 1); - UNSAFE.putObjectVolatile(this, SEGMENTS_OFFSET, oisSegments); - - // set hashMask - UNSAFE.putIntVolatile(this, HASHSEED_OFFSET, - sun.misc.Hashing.randomHashSeed(this)); - - // Re-initialize segments to be minimally sized, and let grow. - int cap = MIN_SEGMENT_TABLE_CAPACITY; - final Segment[] segments = this.segments; - for (int k = 0; k < segments.length; ++k) { - Segment seg = segments[k]; - if (seg != null) { - seg.threshold = (int)(cap * seg.loadFactor); - seg.table = (HashEntry[]) new HashEntry[cap]; + } + + // ------------------------------------------------------- + + // Parallel bulk operations + + /** + * Computes initial batch value for bulk tasks. The returned value + * is approximately exp2 of the number of times (minus one) to + * split task by two before executing leaf action. This value is + * faster to compute and more convenient to use as a guide to + * splitting than is the depth, since it is used while dividing by + * two anyway. + */ + final int batchFor(long b) { + long n; + if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b) + return 0; + int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4 + return (b <= 0L || (n /= b) >= sp) ? sp : (int)n; + } + + /** + * Performs the given action for each (key, value). + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param action the action + */ + public void forEach(long parallelismThreshold, + BiConsumer action) { + if (action == null) throw new NullPointerException(); + new ForEachMappingTask + (null, batchFor(parallelismThreshold), 0, 0, table, + action).invoke(); + } + + /** + * Performs the given action for each non-null transformation + * of each (key, value). + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case the action is not applied) + * @param action the action + */ + public void forEach(long parallelismThreshold, + BiFunction transformer, + Consumer action) { + if (transformer == null || action == null) + throw new NullPointerException(); + new ForEachTransformedMappingTask + (null, batchFor(parallelismThreshold), 0, 0, table, + transformer, action).invoke(); + } + + /** + * Returns a non-null result from applying the given search + * function on each (key, value), or null if none. Upon + * success, further element processing is suppressed and the + * results of any other parallel invocations of the search + * function are ignored. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param searchFunction a function returning a non-null + * result on success, else null + * @return a non-null result from applying the given search + * function on each (key, value), or null if none + */ + public U search(long parallelismThreshold, + BiFunction searchFunction) { + if (searchFunction == null) throw new NullPointerException(); + return new SearchMappingsTask + (null, batchFor(parallelismThreshold), 0, 0, table, + searchFunction, new AtomicReference()).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all (key, value) pairs using the given reducer to + * combine values, or null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case it is not combined) + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all (key, value) pairs + */ + public U reduce(long parallelismThreshold, + BiFunction transformer, + BiFunction reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceMappingsTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all (key, value) pairs using the given reducer to + * combine values, and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all (key, value) pairs + */ + public double reduceToDoubleIn(long parallelismThreshold, + ToDoubleBiFunction transformer, + double basis, + DoubleBinaryOperator reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceMappingsToDoubleTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all (key, value) pairs using the given reducer to + * combine values, and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all (key, value) pairs + */ + public long reduceToLong(long parallelismThreshold, + ToLongBiFunction transformer, + long basis, + LongBinaryOperator reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceMappingsToLongTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all (key, value) pairs using the given reducer to + * combine values, and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all (key, value) pairs + */ + public int reduceToInt(long parallelismThreshold, + ToIntBiFunction transformer, + int basis, + IntBinaryOperator reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceMappingsToIntTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Performs the given action for each key. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param action the action + */ + public void forEachKey(long parallelismThreshold, + Consumer action) { + if (action == null) throw new NullPointerException(); + new ForEachKeyTask + (null, batchFor(parallelismThreshold), 0, 0, table, + action).invoke(); + } + + /** + * Performs the given action for each non-null transformation + * of each key. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case the action is not applied) + * @param action the action + */ + public void forEachKey(long parallelismThreshold, + Function transformer, + Consumer action) { + if (transformer == null || action == null) + throw new NullPointerException(); + new ForEachTransformedKeyTask + (null, batchFor(parallelismThreshold), 0, 0, table, + transformer, action).invoke(); + } + + /** + * Returns a non-null result from applying the given search + * function on each key, or null if none. Upon success, + * further element processing is suppressed and the results of + * any other parallel invocations of the search function are + * ignored. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param searchFunction a function returning a non-null + * result on success, else null + * @return a non-null result from applying the given search + * function on each key, or null if none + */ + public U searchKeys(long parallelismThreshold, + Function searchFunction) { + if (searchFunction == null) throw new NullPointerException(); + return new SearchKeysTask + (null, batchFor(parallelismThreshold), 0, 0, table, + searchFunction, new AtomicReference()).invoke(); + } + + /** + * Returns the result of accumulating all keys using the given + * reducer to combine values, or null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param reducer a commutative associative combining function + * @return the result of accumulating all keys using the given + * reducer to combine values, or null if none + */ + public K reduceKeys(long parallelismThreshold, + BiFunction reducer) { + if (reducer == null) throw new NullPointerException(); + return new ReduceKeysTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all keys using the given reducer to combine values, or + * null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case it is not combined) + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all keys + */ + public U reduceKeys(long parallelismThreshold, + Function transformer, + BiFunction reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceKeysTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all keys using the given reducer to combine values, and + * the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all keys + */ + public double reduceKeysToDouble(long parallelismThreshold, + ToDoubleFunction transformer, + double basis, + DoubleBinaryOperator reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceKeysToDoubleTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all keys using the given reducer to combine values, and + * the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all keys + */ + public long reduceKeysToLong(long parallelismThreshold, + ToLongFunction transformer, + long basis, + LongBinaryOperator reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceKeysToLongTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all keys using the given reducer to combine values, and + * the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all keys + */ + public int reduceKeysToInt(long parallelismThreshold, + ToIntFunction transformer, + int basis, + IntBinaryOperator reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceKeysToIntTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Performs the given action for each value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param action the action + */ + public void forEachValue(long parallelismThreshold, + Consumer action) { + if (action == null) + throw new NullPointerException(); + new ForEachValueTask + (null, batchFor(parallelismThreshold), 0, 0, table, + action).invoke(); + } + + /** + * Performs the given action for each non-null transformation + * of each value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case the action is not applied) + * @param action the action + */ + public void forEachValue(long parallelismThreshold, + Function transformer, + Consumer action) { + if (transformer == null || action == null) + throw new NullPointerException(); + new ForEachTransformedValueTask + (null, batchFor(parallelismThreshold), 0, 0, table, + transformer, action).invoke(); + } + + /** + * Returns a non-null result from applying the given search + * function on each value, or null if none. Upon success, + * further element processing is suppressed and the results of + * any other parallel invocations of the search function are + * ignored. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param searchFunction a function returning a non-null + * result on success, else null + * @return a non-null result from applying the given search + * function on each value, or null if none + */ + public U searchValues(long parallelismThreshold, + Function searchFunction) { + if (searchFunction == null) throw new NullPointerException(); + return new SearchValuesTask + (null, batchFor(parallelismThreshold), 0, 0, table, + searchFunction, new AtomicReference()).invoke(); + } + + /** + * Returns the result of accumulating all values using the + * given reducer to combine values, or null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param reducer a commutative associative combining function + * @return the result of accumulating all values + */ + public V reduceValues(long parallelismThreshold, + BiFunction reducer) { + if (reducer == null) throw new NullPointerException(); + return new ReduceValuesTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all values using the given reducer to combine values, or + * null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case it is not combined) + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all values + */ + public U reduceValues(long parallelismThreshold, + Function transformer, + BiFunction reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceValuesTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all values using the given reducer to combine values, + * and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all values + */ + public double reduceValuesToDouble(long parallelismThreshold, + ToDoubleFunction transformer, + double basis, + DoubleBinaryOperator reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceValuesToDoubleTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all values using the given reducer to combine values, + * and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all values + */ + public long reduceValuesToLong(long parallelismThreshold, + ToLongFunction transformer, + long basis, + LongBinaryOperator reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceValuesToLongTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all values using the given reducer to combine values, + * and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all values + */ + public int reduceValuesToInt(long parallelismThreshold, + ToIntFunction transformer, + int basis, + IntBinaryOperator reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceValuesToIntTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Performs the given action for each entry. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param action the action + */ + public void forEachEntry(long parallelismThreshold, + Consumer> action) { + if (action == null) throw new NullPointerException(); + new ForEachEntryTask(null, batchFor(parallelismThreshold), 0, 0, table, + action).invoke(); + } + + /** + * Performs the given action for each non-null transformation + * of each entry. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case the action is not applied) + * @param action the action + */ + public void forEachEntry(long parallelismThreshold, + Function, ? extends U> transformer, + Consumer action) { + if (transformer == null || action == null) + throw new NullPointerException(); + new ForEachTransformedEntryTask + (null, batchFor(parallelismThreshold), 0, 0, table, + transformer, action).invoke(); + } + + /** + * Returns a non-null result from applying the given search + * function on each entry, or null if none. Upon success, + * further element processing is suppressed and the results of + * any other parallel invocations of the search function are + * ignored. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param searchFunction a function returning a non-null + * result on success, else null + * @return a non-null result from applying the given search + * function on each entry, or null if none + */ + public U searchEntries(long parallelismThreshold, + Function, ? extends U> searchFunction) { + if (searchFunction == null) throw new NullPointerException(); + return new SearchEntriesTask + (null, batchFor(parallelismThreshold), 0, 0, table, + searchFunction, new AtomicReference()).invoke(); + } + + /** + * Returns the result of accumulating all entries using the + * given reducer to combine values, or null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param reducer a commutative associative combining function + * @return the result of accumulating all entries + */ + public Map.Entry reduceEntries(long parallelismThreshold, + BiFunction, Map.Entry, ? extends Map.Entry> reducer) { + if (reducer == null) throw new NullPointerException(); + return new ReduceEntriesTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all entries using the given reducer to combine values, + * or null if none. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element, or null if there is no transformation (in + * which case it is not combined) + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all entries + */ + public U reduceEntries(long parallelismThreshold, + Function, ? extends U> transformer, + BiFunction reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceEntriesTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all entries using the given reducer to combine values, + * and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all entries + */ + public double reduceEntriesToDouble(long parallelismThreshold, + ToDoubleFunction> transformer, + double basis, + DoubleBinaryOperator reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceEntriesToDoubleTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all entries using the given reducer to combine values, + * and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all entries + */ + public long reduceEntriesToLong(long parallelismThreshold, + ToLongFunction> transformer, + long basis, + LongBinaryOperator reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceEntriesToLongTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + /** + * Returns the result of accumulating the given transformation + * of all entries using the given reducer to combine values, + * and the given basis as an identity value. + * + * @param parallelismThreshold the (estimated) number of elements + * needed for this operation to be executed in parallel + * @param transformer a function returning the transformation + * for an element + * @param basis the identity (initial default value) for the reduction + * @param reducer a commutative associative combining function + * @return the result of accumulating the given transformation + * of all entries + */ + public int reduceEntriesToInt(long parallelismThreshold, + ToIntFunction> transformer, + int basis, + IntBinaryOperator reducer) { + if (transformer == null || reducer == null) + throw new NullPointerException(); + return new MapReduceEntriesToIntTask + (null, batchFor(parallelismThreshold), 0, 0, table, + null, transformer, basis, reducer).invoke(); + } + + + /* ----------------Views -------------- */ + + /** + * Base class for views. + */ + abstract static class CollectionView + implements Collection, java.io.Serializable { + private static final long serialVersionUID = 7249069246763182397L; + final ConcurrentHashMap map; + CollectionView(ConcurrentHashMap map) { this.map = map; } + + /** + * Returns the map backing this view. + * + * @return the map backing this view + */ + public ConcurrentHashMap getMap() { return map; } + + /** + * Removes all of the elements from this view, by removing all + * the mappings from the map backing this view. + */ + public final void clear() { map.clear(); } + public final int size() { return map.size(); } + public final boolean isEmpty() { return map.isEmpty(); } + + // implementations below rely on concrete classes supplying these + // abstract methods + /** + * Returns a "weakly consistent" iterator that will never + * throw {@link ConcurrentModificationException}, and + * guarantees to traverse elements as they existed upon + * construction of the iterator, and may (but is not + * guaranteed to) reflect any modifications subsequent to + * construction. + */ + public abstract Iterator iterator(); + public abstract boolean contains(Object o); + public abstract boolean remove(Object o); + + private static final String oomeMsg = "Required array size too large"; + + public final Object[] toArray() { + long sz = map.mappingCount(); + if (sz > MAX_ARRAY_SIZE) + throw new OutOfMemoryError(oomeMsg); + int n = (int)sz; + Object[] r = new Object[n]; + int i = 0; + for (E e : this) { + if (i == n) { + if (n >= MAX_ARRAY_SIZE) + throw new OutOfMemoryError(oomeMsg); + if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) + n = MAX_ARRAY_SIZE; + else + n += (n >>> 1) + 1; + r = Arrays.copyOf(r, n); + } + r[i++] = e; + } + return (i == n) ? r : Arrays.copyOf(r, i); + } + + public final T[] toArray(T[] a) { + long sz = map.mappingCount(); + if (sz > MAX_ARRAY_SIZE) + throw new OutOfMemoryError(oomeMsg); + int m = (int)sz; + T[] r = (a.length >= m) ? a : + (T[])java.lang.reflect.Array + .newInstance(a.getClass().getComponentType(), m); + int n = r.length; + int i = 0; + for (E e : this) { + if (i == n) { + if (n >= MAX_ARRAY_SIZE) + throw new OutOfMemoryError(oomeMsg); + if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) + n = MAX_ARRAY_SIZE; + else + n += (n >>> 1) + 1; + r = Arrays.copyOf(r, n); + } + r[i++] = (T)e; + } + if (a == r && i < n) { + r[i] = null; // null-terminate + return r; + } + return (i == n) ? r : Arrays.copyOf(r, i); + } + + /** + * Returns a string representation of this collection. + * The string representation consists of the string representations + * of the collection's elements in the order they are returned by + * its iterator, enclosed in square brackets ({@code "[]"}). + * Adjacent elements are separated by the characters {@code ", "} + * (comma and space). Elements are converted to strings as by + * {@link String#valueOf(Object)}. + * + * @return a string representation of this collection + */ + public final String toString() { + StringBuilder sb = new StringBuilder(); + sb.append('['); + Iterator it = iterator(); + if (it.hasNext()) { + for (;;) { + Object e = it.next(); + sb.append(e == this ? "(this Collection)" : e); + if (!it.hasNext()) + break; + sb.append(',').append(' '); + } + } + return sb.append(']').toString(); + } + + public final boolean containsAll(Collection c) { + if (c != this) { + for (Object e : c) { + if (e == null || !contains(e)) + return false; + } + } + return true; + } + + public final boolean removeAll(Collection c) { + boolean modified = false; + for (Iterator it = iterator(); it.hasNext();) { + if (c.contains(it.next())) { + it.remove(); + modified = true; + } + } + return modified; + } + + public final boolean retainAll(Collection c) { + boolean modified = false; + for (Iterator it = iterator(); it.hasNext();) { + if (!c.contains(it.next())) { + it.remove(); + modified = true; + } + } + return modified; + } + + } + + /** + * A view of a ConcurrentHashMap as a {@link Set} of keys, in + * which additions may optionally be enabled by mapping to a + * common value. This class cannot be directly instantiated. + * See {@link #keySet() keySet()}, + * {@link #keySet(Object) keySet(V)}, + * {@link #newKeySet() newKeySet()}, + * {@link #newKeySet(int) newKeySet(int)}. + */ + public static class KeySetView extends CollectionView + implements Set, java.io.Serializable { + private static final long serialVersionUID = 7249069246763182397L; + private final V value; + KeySetView(ConcurrentHashMap map, V value) { // non-public + super(map); + this.value = value; + } + + /** + * Returns the default mapped value for additions, + * or {@code null} if additions are not supported. + * + * @return the default mapped value for additions, or {@code null} + * if not supported + */ + public V getMappedValue() { return value; } + + /** + * {@inheritDoc} + * @throws NullPointerException if the specified key is null + */ + public boolean contains(Object o) { return map.containsKey(o); } + + /** + * Removes the key from this map view, by removing the key (and its + * corresponding value) from the backing map. This method does + * nothing if the key is not in the map. + * + * @param o the key to be removed from the backing map + * @return {@code true} if the backing map contained the specified key + * @throws NullPointerException if the specified key is null + */ + public boolean remove(Object o) { return map.remove(o) != null; } + + /** + * @return an iterator over the keys of the backing map + */ + public Iterator iterator() { + Node[] t; + ConcurrentHashMap m = map; + int f = (t = m.table) == null ? 0 : t.length; + return new KeyIterator(t, f, 0, f, m); + } + + /** + * Adds the specified key to this set view by mapping the key to + * the default mapped value in the backing map, if defined. + * + * @param e key to be added + * @return {@code true} if this set changed as a result of the call + * @throws NullPointerException if the specified key is null + * @throws UnsupportedOperationException if no default mapped value + * for additions was provided + */ + public boolean add(K e) { + V v; + if ((v = value) == null) + throw new UnsupportedOperationException(); + return map.internalPut(e, v, true) == null; + } + + /** + * Adds all of the elements in the specified collection to this set, + * as if by calling {@link #add} on each one. + * + * @param c the elements to be inserted into this set + * @return {@code true} if this set changed as a result of the call + * @throws NullPointerException if the collection or any of its + * elements are {@code null} + * @throws UnsupportedOperationException if no default mapped value + * for additions was provided + */ + public boolean addAll(Collection c) { + boolean added = false; + V v; + if ((v = value) == null) + throw new UnsupportedOperationException(); + for (K e : c) { + if (map.internalPut(e, v, true) == null) + added = true; + } + return added; + } + + public int hashCode() { + int h = 0; + for (K e : this) + h += e.hashCode(); + return h; + } + + public boolean equals(Object o) { + Set c; + return ((o instanceof Set) && + ((c = (Set)o) == this || + (containsAll(c) && c.containsAll(this)))); + } + + public Spliterator spliterator() { + Node[] t; + ConcurrentHashMap m = map; + long n = m.sumCount(); + int f = (t = m.table) == null ? 0 : t.length; + return new KeySpliterator(t, f, 0, f, n < 0L ? 0L : n); + } + + public void forEach(Consumer action) { + if (action == null) throw new NullPointerException(); + Node[] t; + if ((t = map.table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) + action.accept((K)p.key); + } + } + } + + /** + * A view of a ConcurrentHashMap as a {@link Collection} of + * values, in which additions are disabled. This class cannot be + * directly instantiated. See {@link #values()}. + */ + static final class ValuesView extends CollectionView + implements Collection, java.io.Serializable { + private static final long serialVersionUID = 2249069246763182397L; + ValuesView(ConcurrentHashMap map) { super(map); } + public final boolean contains(Object o) { + return map.containsValue(o); + } + + public final boolean remove(Object o) { + if (o != null) { + for (Iterator it = iterator(); it.hasNext();) { + if (o.equals(it.next())) { + it.remove(); + return true; + } + } + } + return false; + } + + public final Iterator iterator() { + ConcurrentHashMap m = map; + Node[] t; + int f = (t = m.table) == null ? 0 : t.length; + return new ValueIterator(t, f, 0, f, m); + } + + public final boolean add(V e) { + throw new UnsupportedOperationException(); + } + public final boolean addAll(Collection c) { + throw new UnsupportedOperationException(); + } + + public Spliterator spliterator() { + Node[] t; + ConcurrentHashMap m = map; + long n = m.sumCount(); + int f = (t = m.table) == null ? 0 : t.length; + return new ValueSpliterator(t, f, 0, f, n < 0L ? 0L : n); + } + + public void forEach(Consumer action) { + if (action == null) throw new NullPointerException(); + Node[] t; + if ((t = map.table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) + action.accept(p.val); + } + } + } + + /** + * A view of a ConcurrentHashMap as a {@link Set} of (key, value) + * entries. This class cannot be directly instantiated. See + * {@link #entrySet()}. + */ + static final class EntrySetView extends CollectionView> + implements Set>, java.io.Serializable { + private static final long serialVersionUID = 2249069246763182397L; + EntrySetView(ConcurrentHashMap map) { super(map); } + + public boolean contains(Object o) { + Object k, v, r; Map.Entry e; + return ((o instanceof Map.Entry) && + (k = (e = (Map.Entry)o).getKey()) != null && + (r = map.get(k)) != null && + (v = e.getValue()) != null && + (v == r || v.equals(r))); + } + + public boolean remove(Object o) { + Object k, v; Map.Entry e; + return ((o instanceof Map.Entry) && + (k = (e = (Map.Entry)o).getKey()) != null && + (v = e.getValue()) != null && + map.remove(k, v)); + } + + /** + * @return an iterator over the entries of the backing map + */ + public Iterator> iterator() { + ConcurrentHashMap m = map; + Node[] t; + int f = (t = m.table) == null ? 0 : t.length; + return new EntryIterator(t, f, 0, f, m); + } + + public boolean add(Entry e) { + return map.internalPut(e.getKey(), e.getValue(), false) == null; + } + + public boolean addAll(Collection> c) { + boolean added = false; + for (Entry e : c) { + if (add(e)) + added = true; + } + return added; + } + + public final int hashCode() { + int h = 0; + Node[] t; + if ((t = map.table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) { + h += p.hashCode(); + } + } + return h; + } + + public final boolean equals(Object o) { + Set c; + return ((o instanceof Set) && + ((c = (Set)o) == this || + (containsAll(c) && c.containsAll(this)))); + } + + public Spliterator> spliterator() { + Node[] t; + ConcurrentHashMap m = map; + long n = m.sumCount(); + int f = (t = m.table) == null ? 0 : t.length; + return new EntrySpliterator(t, f, 0, f, n < 0L ? 0L : n, m); + } + + public void forEach(Consumer> action) { + if (action == null) throw new NullPointerException(); + Node[] t; + if ((t = map.table) != null) { + Traverser it = new Traverser(t, t.length, 0, t.length); + for (Node p; (p = it.advance()) != null; ) + action.accept(new MapEntry((K)p.key, p.val, map)); + } + } + + } + + // ------------------------------------------------------- + + /** + * Base class for bulk tasks. Repeats some fields and code from + * class Traverser, because we need to subclass CountedCompleter. + */ + abstract static class BulkTask extends CountedCompleter { + Node[] tab; // same as Traverser + Node next; + int index; + int baseIndex; + int baseLimit; + final int baseSize; + int batch; // split control + + BulkTask(BulkTask par, int b, int i, int f, Node[] t) { + super(par); + this.batch = b; + this.index = this.baseIndex = i; + if ((this.tab = t) == null) + this.baseSize = this.baseLimit = 0; + else if (par == null) + this.baseSize = this.baseLimit = t.length; + else { + this.baseLimit = f; + this.baseSize = par.baseSize; + } + } + + /** + * Same as Traverser version + */ + final Node advance() { + Node e; + if ((e = next) != null) + e = e.next; + for (;;) { + Node[] t; int i, n; Object ek; + if (e != null) + return next = e; + if (baseIndex >= baseLimit || (t = tab) == null || + (n = t.length) <= (i = index) || i < 0) + return next = null; + if ((e = tabAt(t, index)) != null && e.hash < 0) { + if ((ek = e.key) instanceof TreeBin) + e = ((TreeBin)ek).first; + else { + tab = (Node[])ek; + e = null; + continue; + } + } + if ((index += baseSize) >= n) + index = ++baseIndex; } } - - // Read the keys and values, and put the mappings in the table - for (;;) { - K key = (K) s.readObject(); - V value = (V) s.readObject(); - if (key == null) - break; - put(key, value); + } + + /* + * Task classes. Coded in a regular but ugly format/style to + * simplify checks that each variant differs in the right way from + * others. The null screenings exist because compilers cannot tell + * that we've already null-checked task arguments, so we force + * simplest hoisted bypass to help avoid convoluted traps. + */ + + static final class ForEachKeyTask + extends BulkTask { + final Consumer action; + ForEachKeyTask + (BulkTask p, int b, int i, int f, Node[] t, + Consumer action) { + super(p, b, i, f, t); + this.action = action; + } + public final void compute() { + final Consumer action; + if ((action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachKeyTask + (this, batch >>>= 1, baseLimit = h, f, tab, + action).fork(); + } + for (Node p; (p = advance()) != null;) + action.accept((K)p.key); + propagateCompletion(); + } + } + } + + static final class ForEachValueTask + extends BulkTask { + final Consumer action; + ForEachValueTask + (BulkTask p, int b, int i, int f, Node[] t, + Consumer action) { + super(p, b, i, f, t); + this.action = action; + } + public final void compute() { + final Consumer action; + if ((action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachValueTask + (this, batch >>>= 1, baseLimit = h, f, tab, + action).fork(); + } + for (Node p; (p = advance()) != null;) + action.accept(p.val); + propagateCompletion(); + } + } + } + + static final class ForEachEntryTask + extends BulkTask { + final Consumer> action; + ForEachEntryTask + (BulkTask p, int b, int i, int f, Node[] t, + Consumer> action) { + super(p, b, i, f, t); + this.action = action; + } + public final void compute() { + final Consumer> action; + if ((action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachEntryTask + (this, batch >>>= 1, baseLimit = h, f, tab, + action).fork(); + } + for (Node p; (p = advance()) != null; ) + action.accept(p); + propagateCompletion(); + } + } + } + + static final class ForEachMappingTask + extends BulkTask { + final BiConsumer action; + ForEachMappingTask + (BulkTask p, int b, int i, int f, Node[] t, + BiConsumer action) { + super(p, b, i, f, t); + this.action = action; + } + public final void compute() { + final BiConsumer action; + if ((action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachMappingTask + (this, batch >>>= 1, baseLimit = h, f, tab, + action).fork(); + } + for (Node p; (p = advance()) != null; ) + action.accept((K)p.key, p.val); + propagateCompletion(); + } + } + } + + static final class ForEachTransformedKeyTask + extends BulkTask { + final Function transformer; + final Consumer action; + ForEachTransformedKeyTask + (BulkTask p, int b, int i, int f, Node[] t, + Function transformer, Consumer action) { + super(p, b, i, f, t); + this.transformer = transformer; this.action = action; + } + public final void compute() { + final Function transformer; + final Consumer action; + if ((transformer = this.transformer) != null && + (action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachTransformedKeyTask + (this, batch >>>= 1, baseLimit = h, f, tab, + transformer, action).fork(); + } + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply((K)p.key)) != null) + action.accept(u); + } + propagateCompletion(); + } + } + } + + static final class ForEachTransformedValueTask + extends BulkTask { + final Function transformer; + final Consumer action; + ForEachTransformedValueTask + (BulkTask p, int b, int i, int f, Node[] t, + Function transformer, Consumer action) { + super(p, b, i, f, t); + this.transformer = transformer; this.action = action; + } + public final void compute() { + final Function transformer; + final Consumer action; + if ((transformer = this.transformer) != null && + (action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachTransformedValueTask + (this, batch >>>= 1, baseLimit = h, f, tab, + transformer, action).fork(); + } + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply(p.val)) != null) + action.accept(u); + } + propagateCompletion(); + } + } + } + + static final class ForEachTransformedEntryTask + extends BulkTask { + final Function, ? extends U> transformer; + final Consumer action; + ForEachTransformedEntryTask + (BulkTask p, int b, int i, int f, Node[] t, + Function, ? extends U> transformer, Consumer action) { + super(p, b, i, f, t); + this.transformer = transformer; this.action = action; + } + public final void compute() { + final Function, ? extends U> transformer; + final Consumer action; + if ((transformer = this.transformer) != null && + (action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachTransformedEntryTask + (this, batch >>>= 1, baseLimit = h, f, tab, + transformer, action).fork(); + } + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply(p)) != null) + action.accept(u); + } + propagateCompletion(); + } + } + } + + static final class ForEachTransformedMappingTask + extends BulkTask { + final BiFunction transformer; + final Consumer action; + ForEachTransformedMappingTask + (BulkTask p, int b, int i, int f, Node[] t, + BiFunction transformer, + Consumer action) { + super(p, b, i, f, t); + this.transformer = transformer; this.action = action; + } + public final void compute() { + final BiFunction transformer; + final Consumer action; + if ((transformer = this.transformer) != null && + (action = this.action) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + new ForEachTransformedMappingTask + (this, batch >>>= 1, baseLimit = h, f, tab, + transformer, action).fork(); + } + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply((K)p.key, p.val)) != null) + action.accept(u); + } + propagateCompletion(); + } + } + } + + static final class SearchKeysTask + extends BulkTask { + final Function searchFunction; + final AtomicReference result; + SearchKeysTask + (BulkTask p, int b, int i, int f, Node[] t, + Function searchFunction, + AtomicReference result) { + super(p, b, i, f, t); + this.searchFunction = searchFunction; this.result = result; + } + public final U getRawResult() { return result.get(); } + public final void compute() { + final Function searchFunction; + final AtomicReference result; + if ((searchFunction = this.searchFunction) != null && + (result = this.result) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + if (result.get() != null) + return; + addToPendingCount(1); + new SearchKeysTask + (this, batch >>>= 1, baseLimit = h, f, tab, + searchFunction, result).fork(); + } + while (result.get() == null) { + U u; + Node p; + if ((p = advance()) == null) { + propagateCompletion(); + break; + } + if ((u = searchFunction.apply((K)p.key)) != null) { + if (result.compareAndSet(null, u)) + quietlyCompleteRoot(); + break; + } + } + } + } + } + + static final class SearchValuesTask + extends BulkTask { + final Function searchFunction; + final AtomicReference result; + SearchValuesTask + (BulkTask p, int b, int i, int f, Node[] t, + Function searchFunction, + AtomicReference result) { + super(p, b, i, f, t); + this.searchFunction = searchFunction; this.result = result; + } + public final U getRawResult() { return result.get(); } + public final void compute() { + final Function searchFunction; + final AtomicReference result; + if ((searchFunction = this.searchFunction) != null && + (result = this.result) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + if (result.get() != null) + return; + addToPendingCount(1); + new SearchValuesTask + (this, batch >>>= 1, baseLimit = h, f, tab, + searchFunction, result).fork(); + } + while (result.get() == null) { + U u; + Node p; + if ((p = advance()) == null) { + propagateCompletion(); + break; + } + if ((u = searchFunction.apply(p.val)) != null) { + if (result.compareAndSet(null, u)) + quietlyCompleteRoot(); + break; + } + } + } + } + } + + static final class SearchEntriesTask + extends BulkTask { + final Function, ? extends U> searchFunction; + final AtomicReference result; + SearchEntriesTask + (BulkTask p, int b, int i, int f, Node[] t, + Function, ? extends U> searchFunction, + AtomicReference result) { + super(p, b, i, f, t); + this.searchFunction = searchFunction; this.result = result; + } + public final U getRawResult() { return result.get(); } + public final void compute() { + final Function, ? extends U> searchFunction; + final AtomicReference result; + if ((searchFunction = this.searchFunction) != null && + (result = this.result) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + if (result.get() != null) + return; + addToPendingCount(1); + new SearchEntriesTask + (this, batch >>>= 1, baseLimit = h, f, tab, + searchFunction, result).fork(); + } + while (result.get() == null) { + U u; + Node p; + if ((p = advance()) == null) { + propagateCompletion(); + break; + } + if ((u = searchFunction.apply(p)) != null) { + if (result.compareAndSet(null, u)) + quietlyCompleteRoot(); + return; + } + } + } + } + } + + static final class SearchMappingsTask + extends BulkTask { + final BiFunction searchFunction; + final AtomicReference result; + SearchMappingsTask + (BulkTask p, int b, int i, int f, Node[] t, + BiFunction searchFunction, + AtomicReference result) { + super(p, b, i, f, t); + this.searchFunction = searchFunction; this.result = result; + } + public final U getRawResult() { return result.get(); } + public final void compute() { + final BiFunction searchFunction; + final AtomicReference result; + if ((searchFunction = this.searchFunction) != null && + (result = this.result) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + if (result.get() != null) + return; + addToPendingCount(1); + new SearchMappingsTask + (this, batch >>>= 1, baseLimit = h, f, tab, + searchFunction, result).fork(); + } + while (result.get() == null) { + U u; + Node p; + if ((p = advance()) == null) { + propagateCompletion(); + break; + } + if ((u = searchFunction.apply((K)p.key, p.val)) != null) { + if (result.compareAndSet(null, u)) + quietlyCompleteRoot(); + break; + } + } + } + } + } + + static final class ReduceKeysTask + extends BulkTask { + final BiFunction reducer; + K result; + ReduceKeysTask rights, nextRight; + ReduceKeysTask + (BulkTask p, int b, int i, int f, Node[] t, + ReduceKeysTask nextRight, + BiFunction reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.reducer = reducer; + } + public final K getRawResult() { return result; } + public final void compute() { + final BiFunction reducer; + if ((reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new ReduceKeysTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, reducer)).fork(); + } + K r = null; + for (Node p; (p = advance()) != null; ) { + K u = (K)p.key; + r = (r == null) ? u : u == null ? r : reducer.apply(r, u); + } + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + ReduceKeysTask + t = (ReduceKeysTask)c, + s = t.rights; + while (s != null) { + K tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class ReduceValuesTask + extends BulkTask { + final BiFunction reducer; + V result; + ReduceValuesTask rights, nextRight; + ReduceValuesTask + (BulkTask p, int b, int i, int f, Node[] t, + ReduceValuesTask nextRight, + BiFunction reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.reducer = reducer; + } + public final V getRawResult() { return result; } + public final void compute() { + final BiFunction reducer; + if ((reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new ReduceValuesTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, reducer)).fork(); + } + V r = null; + for (Node p; (p = advance()) != null; ) { + V v = p.val; + r = (r == null) ? v : reducer.apply(r, v); + } + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + ReduceValuesTask + t = (ReduceValuesTask)c, + s = t.rights; + while (s != null) { + V tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class ReduceEntriesTask + extends BulkTask> { + final BiFunction, Map.Entry, ? extends Map.Entry> reducer; + Map.Entry result; + ReduceEntriesTask rights, nextRight; + ReduceEntriesTask + (BulkTask p, int b, int i, int f, Node[] t, + ReduceEntriesTask nextRight, + BiFunction, Map.Entry, ? extends Map.Entry> reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.reducer = reducer; + } + public final Map.Entry getRawResult() { return result; } + public final void compute() { + final BiFunction, Map.Entry, ? extends Map.Entry> reducer; + if ((reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new ReduceEntriesTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, reducer)).fork(); + } + Map.Entry r = null; + for (Node p; (p = advance()) != null; ) + r = (r == null) ? p : reducer.apply(r, p); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + ReduceEntriesTask + t = (ReduceEntriesTask)c, + s = t.rights; + while (s != null) { + Map.Entry tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceKeysTask + extends BulkTask { + final Function transformer; + final BiFunction reducer; + U result; + MapReduceKeysTask rights, nextRight; + MapReduceKeysTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceKeysTask nextRight, + Function transformer, + BiFunction reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.reducer = reducer; + } + public final U getRawResult() { return result; } + public final void compute() { + final Function transformer; + final BiFunction reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceKeysTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, reducer)).fork(); + } + U r = null; + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply((K)p.key)) != null) + r = (r == null) ? u : reducer.apply(r, u); + } + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceKeysTask + t = (MapReduceKeysTask)c, + s = t.rights; + while (s != null) { + U tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceValuesTask + extends BulkTask { + final Function transformer; + final BiFunction reducer; + U result; + MapReduceValuesTask rights, nextRight; + MapReduceValuesTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceValuesTask nextRight, + Function transformer, + BiFunction reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.reducer = reducer; + } + public final U getRawResult() { return result; } + public final void compute() { + final Function transformer; + final BiFunction reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceValuesTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, reducer)).fork(); + } + U r = null; + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply(p.val)) != null) + r = (r == null) ? u : reducer.apply(r, u); + } + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceValuesTask + t = (MapReduceValuesTask)c, + s = t.rights; + while (s != null) { + U tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceEntriesTask + extends BulkTask { + final Function, ? extends U> transformer; + final BiFunction reducer; + U result; + MapReduceEntriesTask rights, nextRight; + MapReduceEntriesTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceEntriesTask nextRight, + Function, ? extends U> transformer, + BiFunction reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.reducer = reducer; + } + public final U getRawResult() { return result; } + public final void compute() { + final Function, ? extends U> transformer; + final BiFunction reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceEntriesTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, reducer)).fork(); + } + U r = null; + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply(p)) != null) + r = (r == null) ? u : reducer.apply(r, u); + } + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceEntriesTask + t = (MapReduceEntriesTask)c, + s = t.rights; + while (s != null) { + U tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceMappingsTask + extends BulkTask { + final BiFunction transformer; + final BiFunction reducer; + U result; + MapReduceMappingsTask rights, nextRight; + MapReduceMappingsTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceMappingsTask nextRight, + BiFunction transformer, + BiFunction reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.reducer = reducer; + } + public final U getRawResult() { return result; } + public final void compute() { + final BiFunction transformer; + final BiFunction reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceMappingsTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, reducer)).fork(); + } + U r = null; + for (Node p; (p = advance()) != null; ) { + U u; + if ((u = transformer.apply((K)p.key, p.val)) != null) + r = (r == null) ? u : reducer.apply(r, u); + } + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceMappingsTask + t = (MapReduceMappingsTask)c, + s = t.rights; + while (s != null) { + U tr, sr; + if ((sr = s.result) != null) + t.result = (((tr = t.result) == null) ? sr : + reducer.apply(tr, sr)); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceKeysToDoubleTask + extends BulkTask { + final ToDoubleFunction transformer; + final DoubleBinaryOperator reducer; + final double basis; + double result; + MapReduceKeysToDoubleTask rights, nextRight; + MapReduceKeysToDoubleTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceKeysToDoubleTask nextRight, + ToDoubleFunction transformer, + double basis, + DoubleBinaryOperator reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Double getRawResult() { return result; } + public final void compute() { + final ToDoubleFunction transformer; + final DoubleBinaryOperator reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + double r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceKeysToDoubleTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.applyAsDouble(r, transformer.applyAsDouble((K)p.key)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceKeysToDoubleTask + t = (MapReduceKeysToDoubleTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.applyAsDouble(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceValuesToDoubleTask + extends BulkTask { + final ToDoubleFunction transformer; + final DoubleBinaryOperator reducer; + final double basis; + double result; + MapReduceValuesToDoubleTask rights, nextRight; + MapReduceValuesToDoubleTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceValuesToDoubleTask nextRight, + ToDoubleFunction transformer, + double basis, + DoubleBinaryOperator reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Double getRawResult() { return result; } + public final void compute() { + final ToDoubleFunction transformer; + final DoubleBinaryOperator reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + double r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceValuesToDoubleTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceValuesToDoubleTask + t = (MapReduceValuesToDoubleTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.applyAsDouble(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceEntriesToDoubleTask + extends BulkTask { + final ToDoubleFunction> transformer; + final DoubleBinaryOperator reducer; + final double basis; + double result; + MapReduceEntriesToDoubleTask rights, nextRight; + MapReduceEntriesToDoubleTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceEntriesToDoubleTask nextRight, + ToDoubleFunction> transformer, + double basis, + DoubleBinaryOperator reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Double getRawResult() { return result; } + public final void compute() { + final ToDoubleFunction> transformer; + final DoubleBinaryOperator reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + double r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceEntriesToDoubleTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.applyAsDouble(r, transformer.applyAsDouble(p)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceEntriesToDoubleTask + t = (MapReduceEntriesToDoubleTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.applyAsDouble(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceMappingsToDoubleTask + extends BulkTask { + final ToDoubleBiFunction transformer; + final DoubleBinaryOperator reducer; + final double basis; + double result; + MapReduceMappingsToDoubleTask rights, nextRight; + MapReduceMappingsToDoubleTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceMappingsToDoubleTask nextRight, + ToDoubleBiFunction transformer, + double basis, + DoubleBinaryOperator reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Double getRawResult() { return result; } + public final void compute() { + final ToDoubleBiFunction transformer; + final DoubleBinaryOperator reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + double r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceMappingsToDoubleTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.applyAsDouble(r, transformer.applyAsDouble((K)p.key, p.val)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceMappingsToDoubleTask + t = (MapReduceMappingsToDoubleTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.applyAsDouble(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceKeysToLongTask + extends BulkTask { + final ToLongFunction transformer; + final LongBinaryOperator reducer; + final long basis; + long result; + MapReduceKeysToLongTask rights, nextRight; + MapReduceKeysToLongTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceKeysToLongTask nextRight, + ToLongFunction transformer, + long basis, + LongBinaryOperator reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Long getRawResult() { return result; } + public final void compute() { + final ToLongFunction transformer; + final LongBinaryOperator reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + long r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceKeysToLongTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.applyAsLong(r, transformer.applyAsLong((K)p.key)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceKeysToLongTask + t = (MapReduceKeysToLongTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.applyAsLong(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceValuesToLongTask + extends BulkTask { + final ToLongFunction transformer; + final LongBinaryOperator reducer; + final long basis; + long result; + MapReduceValuesToLongTask rights, nextRight; + MapReduceValuesToLongTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceValuesToLongTask nextRight, + ToLongFunction transformer, + long basis, + LongBinaryOperator reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Long getRawResult() { return result; } + public final void compute() { + final ToLongFunction transformer; + final LongBinaryOperator reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + long r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceValuesToLongTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.applyAsLong(r, transformer.applyAsLong(p.val)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceValuesToLongTask + t = (MapReduceValuesToLongTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.applyAsLong(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceEntriesToLongTask + extends BulkTask { + final ToLongFunction> transformer; + final LongBinaryOperator reducer; + final long basis; + long result; + MapReduceEntriesToLongTask rights, nextRight; + MapReduceEntriesToLongTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceEntriesToLongTask nextRight, + ToLongFunction> transformer, + long basis, + LongBinaryOperator reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Long getRawResult() { return result; } + public final void compute() { + final ToLongFunction> transformer; + final LongBinaryOperator reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + long r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceEntriesToLongTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.applyAsLong(r, transformer.applyAsLong(p)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceEntriesToLongTask + t = (MapReduceEntriesToLongTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.applyAsLong(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceMappingsToLongTask + extends BulkTask { + final ToLongBiFunction transformer; + final LongBinaryOperator reducer; + final long basis; + long result; + MapReduceMappingsToLongTask rights, nextRight; + MapReduceMappingsToLongTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceMappingsToLongTask nextRight, + ToLongBiFunction transformer, + long basis, + LongBinaryOperator reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Long getRawResult() { return result; } + public final void compute() { + final ToLongBiFunction transformer; + final LongBinaryOperator reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + long r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceMappingsToLongTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.applyAsLong(r, transformer.applyAsLong((K)p.key, p.val)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceMappingsToLongTask + t = (MapReduceMappingsToLongTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.applyAsLong(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceKeysToIntTask + extends BulkTask { + final ToIntFunction transformer; + final IntBinaryOperator reducer; + final int basis; + int result; + MapReduceKeysToIntTask rights, nextRight; + MapReduceKeysToIntTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceKeysToIntTask nextRight, + ToIntFunction transformer, + int basis, + IntBinaryOperator reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Integer getRawResult() { return result; } + public final void compute() { + final ToIntFunction transformer; + final IntBinaryOperator reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + int r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceKeysToIntTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.applyAsInt(r, transformer.applyAsInt((K)p.key)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceKeysToIntTask + t = (MapReduceKeysToIntTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.applyAsInt(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceValuesToIntTask + extends BulkTask { + final ToIntFunction transformer; + final IntBinaryOperator reducer; + final int basis; + int result; + MapReduceValuesToIntTask rights, nextRight; + MapReduceValuesToIntTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceValuesToIntTask nextRight, + ToIntFunction transformer, + int basis, + IntBinaryOperator reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Integer getRawResult() { return result; } + public final void compute() { + final ToIntFunction transformer; + final IntBinaryOperator reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + int r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceValuesToIntTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.applyAsInt(r, transformer.applyAsInt(p.val)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceValuesToIntTask + t = (MapReduceValuesToIntTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.applyAsInt(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceEntriesToIntTask + extends BulkTask { + final ToIntFunction> transformer; + final IntBinaryOperator reducer; + final int basis; + int result; + MapReduceEntriesToIntTask rights, nextRight; + MapReduceEntriesToIntTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceEntriesToIntTask nextRight, + ToIntFunction> transformer, + int basis, + IntBinaryOperator reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Integer getRawResult() { return result; } + public final void compute() { + final ToIntFunction> transformer; + final IntBinaryOperator reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + int r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceEntriesToIntTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.applyAsInt(r, transformer.applyAsInt(p)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceEntriesToIntTask + t = (MapReduceEntriesToIntTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.applyAsInt(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } + } + } + + static final class MapReduceMappingsToIntTask + extends BulkTask { + final ToIntBiFunction transformer; + final IntBinaryOperator reducer; + final int basis; + int result; + MapReduceMappingsToIntTask rights, nextRight; + MapReduceMappingsToIntTask + (BulkTask p, int b, int i, int f, Node[] t, + MapReduceMappingsToIntTask nextRight, + ToIntBiFunction transformer, + int basis, + IntBinaryOperator reducer) { + super(p, b, i, f, t); this.nextRight = nextRight; + this.transformer = transformer; + this.basis = basis; this.reducer = reducer; + } + public final Integer getRawResult() { return result; } + public final void compute() { + final ToIntBiFunction transformer; + final IntBinaryOperator reducer; + if ((transformer = this.transformer) != null && + (reducer = this.reducer) != null) { + int r = this.basis; + for (int i = baseIndex, f, h; batch > 0 && + (h = ((f = baseLimit) + i) >>> 1) > i;) { + addToPendingCount(1); + (rights = new MapReduceMappingsToIntTask + (this, batch >>>= 1, baseLimit = h, f, tab, + rights, transformer, r, reducer)).fork(); + } + for (Node p; (p = advance()) != null; ) + r = reducer.applyAsInt(r, transformer.applyAsInt((K)p.key, p.val)); + result = r; + CountedCompleter c; + for (c = firstComplete(); c != null; c = c.nextComplete()) { + MapReduceMappingsToIntTask + t = (MapReduceMappingsToIntTask)c, + s = t.rights; + while (s != null) { + t.result = reducer.applyAsInt(t.result, s.result); + s = t.rights = s.nextRight; + } + } + } } } // Unsafe mechanics - private static final sun.misc.Unsafe UNSAFE; - private static final long SBASE; - private static final int SSHIFT; - private static final long TBASE; - private static final int TSHIFT; - private static final long HASHSEED_OFFSET; - private static final long SEGSHIFT_OFFSET; - private static final long SEGMASK_OFFSET; - private static final long SEGMENTS_OFFSET; + private static final sun.misc.Unsafe U; + private static final long SIZECTL; + private static final long TRANSFERINDEX; + private static final long TRANSFERORIGIN; + private static final long BASECOUNT; + private static final long CELLSBUSY; + private static final long CELLVALUE; + private static final long ABASE; + private static final int ASHIFT; static { - int ss, ts; try { - UNSAFE = sun.misc.Unsafe.getUnsafe(); - Class tc = HashEntry[].class; - Class sc = Segment[].class; - TBASE = UNSAFE.arrayBaseOffset(tc); - SBASE = UNSAFE.arrayBaseOffset(sc); - ts = UNSAFE.arrayIndexScale(tc); - ss = UNSAFE.arrayIndexScale(sc); - HASHSEED_OFFSET = UNSAFE.objectFieldOffset( - ConcurrentHashMap.class.getDeclaredField("hashSeed")); - SEGSHIFT_OFFSET = UNSAFE.objectFieldOffset( - ConcurrentHashMap.class.getDeclaredField("segmentShift")); - SEGMASK_OFFSET = UNSAFE.objectFieldOffset( - ConcurrentHashMap.class.getDeclaredField("segmentMask")); - SEGMENTS_OFFSET = UNSAFE.objectFieldOffset( - ConcurrentHashMap.class.getDeclaredField("segments")); + U = sun.misc.Unsafe.getUnsafe(); + Class k = ConcurrentHashMap.class; + SIZECTL = U.objectFieldOffset + (k.getDeclaredField("sizeCtl")); + TRANSFERINDEX = U.objectFieldOffset + (k.getDeclaredField("transferIndex")); + TRANSFERORIGIN = U.objectFieldOffset + (k.getDeclaredField("transferOrigin")); + BASECOUNT = U.objectFieldOffset + (k.getDeclaredField("baseCount")); + CELLSBUSY = U.objectFieldOffset + (k.getDeclaredField("cellsBusy")); + Class ck = Cell.class; + CELLVALUE = U.objectFieldOffset + (ck.getDeclaredField("value")); + Class sc = Node[].class; + ABASE = U.arrayBaseOffset(sc); + int scale = U.arrayIndexScale(sc); + if ((scale & (scale - 1)) != 0) + throw new Error("data type scale not a power of two"); + ASHIFT = 31 - Integer.numberOfLeadingZeros(scale); } catch (Exception e) { throw new Error(e); } - if ((ss & (ss-1)) != 0 || (ts & (ts-1)) != 0) - throw new Error("data type scale not a power of two"); - SSHIFT = 31 - Integer.numberOfLeadingZeros(ss); - TSHIFT = 31 - Integer.numberOfLeadingZeros(ts); } - }