--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/util/TreeSet.java Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,560 @@
+/*
+ * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.util;
+
+/**
+ * A {@link NavigableSet} implementation based on a {@link TreeMap}.
+ * The elements are ordered using their {@linkplain Comparable natural
+ * ordering}, or by a {@link Comparator} provided at set creation
+ * time, depending on which constructor is used.
+ *
+ * <p>This implementation provides guaranteed log(n) time cost for the basic
+ * operations ({@code add}, {@code remove} and {@code contains}).
+ *
+ * <p>Note that the ordering maintained by a set (whether or not an explicit
+ * comparator is provided) must be <i>consistent with equals</i> if it is to
+ * correctly implement the {@code Set} interface. (See {@code Comparable}
+ * or {@code Comparator} for a precise definition of <i>consistent with
+ * equals</i>.) This is so because the {@code Set} interface is defined in
+ * terms of the {@code equals} operation, but a {@code TreeSet} instance
+ * performs all element comparisons using its {@code compareTo} (or
+ * {@code compare}) method, so two elements that are deemed equal by this method
+ * are, from the standpoint of the set, equal. The behavior of a set
+ * <i>is</i> well-defined even if its ordering is inconsistent with equals; it
+ * just fails to obey the general contract of the {@code Set} interface.
+ *
+ * <p><strong>Note that this implementation is not synchronized.</strong>
+ * If multiple threads access a tree set concurrently, and at least one
+ * of the threads modifies the set, it <i>must</i> be synchronized
+ * externally. This is typically accomplished by synchronizing on some
+ * object that naturally encapsulates the set.
+ * If no such object exists, the set should be "wrapped" using the
+ * {@link Collections#synchronizedSortedSet Collections.synchronizedSortedSet}
+ * method. This is best done at creation time, to prevent accidental
+ * unsynchronized access to the set: <pre>
+ * SortedSet s = Collections.synchronizedSortedSet(new TreeSet(...));</pre>
+ *
+ * <p>The iterators returned by this class's {@code iterator} method are
+ * <i>fail-fast</i>: if the set is modified at any time after the iterator is
+ * created, in any way except through the iterator's own {@code remove}
+ * method, the iterator will throw a {@link ConcurrentModificationException}.
+ * Thus, in the face of concurrent modification, the iterator fails quickly
+ * and cleanly, rather than risking arbitrary, non-deterministic behavior at
+ * an undetermined time in the future.
+ *
+ * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
+ * as it is, generally speaking, impossible to make any hard guarantees in the
+ * presence of unsynchronized concurrent modification. Fail-fast iterators
+ * throw {@code ConcurrentModificationException} on a best-effort basis.
+ * Therefore, it would be wrong to write a program that depended on this
+ * exception for its correctness: <i>the fail-fast behavior of iterators
+ * should be used only to detect bugs.</i>
+ *
+ * <p>This class is a member of the
+ * <a href="{@docRoot}/java/util/package-summary.html#CollectionsFramework">
+ * Java Collections Framework</a>.
+ *
+ * @param <E> the type of elements maintained by this set
+ *
+ * @author Josh Bloch
+ * @see Collection
+ * @see Set
+ * @see HashSet
+ * @see Comparable
+ * @see Comparator
+ * @see TreeMap
+ * @since 1.2
+ */
+
+public class TreeSet<E> extends AbstractSet<E>
+ implements NavigableSet<E>, Cloneable, java.io.Serializable
+{
+ /**
+ * The backing map.
+ */
+ private transient NavigableMap<E,Object> m;
+
+ // Dummy value to associate with an Object in the backing Map
+ private static final Object PRESENT = new Object();
+
+ /**
+ * Constructs a set backed by the specified navigable map.
+ */
+ TreeSet(NavigableMap<E,Object> m) {
+ this.m = m;
+ }
+
+ /**
+ * Constructs a new, empty tree set, sorted according to the
+ * natural ordering of its elements. All elements inserted into
+ * the set must implement the {@link Comparable} interface.
+ * Furthermore, all such elements must be <i>mutually
+ * comparable</i>: {@code e1.compareTo(e2)} must not throw a
+ * {@code ClassCastException} for any elements {@code e1} and
+ * {@code e2} in the set. If the user attempts to add an element
+ * to the set that violates this constraint (for example, the user
+ * attempts to add a string element to a set whose elements are
+ * integers), the {@code add} call will throw a
+ * {@code ClassCastException}.
+ */
+ public TreeSet() {
+ this(new TreeMap<>());
+ }
+
+ /**
+ * Constructs a new, empty tree set, sorted according to the specified
+ * comparator. All elements inserted into the set must be <i>mutually
+ * comparable</i> by the specified comparator: {@code comparator.compare(e1,
+ * e2)} must not throw a {@code ClassCastException} for any elements
+ * {@code e1} and {@code e2} in the set. If the user attempts to add
+ * an element to the set that violates this constraint, the
+ * {@code add} call will throw a {@code ClassCastException}.
+ *
+ * @param comparator the comparator that will be used to order this set.
+ * If {@code null}, the {@linkplain Comparable natural
+ * ordering} of the elements will be used.
+ */
+ public TreeSet(Comparator<? super E> comparator) {
+ this(new TreeMap<>(comparator));
+ }
+
+ /**
+ * Constructs a new tree set containing the elements in the specified
+ * collection, sorted according to the <i>natural ordering</i> of its
+ * elements. All elements inserted into the set must implement the
+ * {@link Comparable} interface. Furthermore, all such elements must be
+ * <i>mutually comparable</i>: {@code e1.compareTo(e2)} must not throw a
+ * {@code ClassCastException} for any elements {@code e1} and
+ * {@code e2} in the set.
+ *
+ * @param c collection whose elements will comprise the new set
+ * @throws ClassCastException if the elements in {@code c} are
+ * not {@link Comparable}, or are not mutually comparable
+ * @throws NullPointerException if the specified collection is null
+ */
+ public TreeSet(Collection<? extends E> c) {
+ this();
+ addAll(c);
+ }
+
+ /**
+ * Constructs a new tree set containing the same elements and
+ * using the same ordering as the specified sorted set.
+ *
+ * @param s sorted set whose elements will comprise the new set
+ * @throws NullPointerException if the specified sorted set is null
+ */
+ public TreeSet(SortedSet<E> s) {
+ this(s.comparator());
+ addAll(s);
+ }
+
+ /**
+ * Returns an iterator over the elements in this set in ascending order.
+ *
+ * @return an iterator over the elements in this set in ascending order
+ */
+ public Iterator<E> iterator() {
+ return m.navigableKeySet().iterator();
+ }
+
+ /**
+ * Returns an iterator over the elements in this set in descending order.
+ *
+ * @return an iterator over the elements in this set in descending order
+ * @since 1.6
+ */
+ public Iterator<E> descendingIterator() {
+ return m.descendingKeySet().iterator();
+ }
+
+ /**
+ * @since 1.6
+ */
+ public NavigableSet<E> descendingSet() {
+ return new TreeSet<>(m.descendingMap());
+ }
+
+ /**
+ * Returns the number of elements in this set (its cardinality).
+ *
+ * @return the number of elements in this set (its cardinality)
+ */
+ public int size() {
+ return m.size();
+ }
+
+ /**
+ * Returns {@code true} if this set contains no elements.
+ *
+ * @return {@code true} if this set contains no elements
+ */
+ public boolean isEmpty() {
+ return m.isEmpty();
+ }
+
+ /**
+ * Returns {@code true} if this set contains the specified element.
+ * More formally, returns {@code true} if and only if this set
+ * contains an element {@code e} such that
+ * {@code Objects.equals(o, e)}.
+ *
+ * @param o object to be checked for containment in this set
+ * @return {@code true} if this set contains the specified element
+ * @throws ClassCastException if the specified object cannot be compared
+ * with the elements currently in the set
+ * @throws NullPointerException if the specified element is null
+ * and this set uses natural ordering, or its comparator
+ * does not permit null elements
+ */
+ public boolean contains(Object o) {
+ return m.containsKey(o);
+ }
+
+ /**
+ * Adds the specified element to this set if it is not already present.
+ * More formally, adds the specified element {@code e} to this set if
+ * the set contains no element {@code e2} such that
+ * {@code Objects.equals(e, e2)}.
+ * If this set already contains the element, the call leaves the set
+ * unchanged and returns {@code false}.
+ *
+ * @param e element to be added to this set
+ * @return {@code true} if this set did not already contain the specified
+ * element
+ * @throws ClassCastException if the specified object cannot be compared
+ * with the elements currently in this set
+ * @throws NullPointerException if the specified element is null
+ * and this set uses natural ordering, or its comparator
+ * does not permit null elements
+ */
+ public boolean add(E e) {
+ return m.put(e, PRESENT)==null;
+ }
+
+ /**
+ * Removes the specified element from this set if it is present.
+ * More formally, removes an element {@code e} such that
+ * {@code Objects.equals(o, e)},
+ * if this set contains such an element. Returns {@code true} if
+ * this set contained the element (or equivalently, if this set
+ * changed as a result of the call). (This set will not contain the
+ * element once the call returns.)
+ *
+ * @param o object to be removed from this set, if present
+ * @return {@code true} if this set contained the specified element
+ * @throws ClassCastException if the specified object cannot be compared
+ * with the elements currently in this set
+ * @throws NullPointerException if the specified element is null
+ * and this set uses natural ordering, or its comparator
+ * does not permit null elements
+ */
+ public boolean remove(Object o) {
+ return m.remove(o)==PRESENT;
+ }
+
+ /**
+ * Removes all of the elements from this set.
+ * The set will be empty after this call returns.
+ */
+ public void clear() {
+ m.clear();
+ }
+
+ /**
+ * Adds all of the elements in the specified collection to this set.
+ *
+ * @param c collection containing elements to be added to this set
+ * @return {@code true} if this set changed as a result of the call
+ * @throws ClassCastException if the elements provided cannot be compared
+ * with the elements currently in the set
+ * @throws NullPointerException if the specified collection is null or
+ * if any element is null and this set uses natural ordering, or
+ * its comparator does not permit null elements
+ */
+ public boolean addAll(Collection<? extends E> c) {
+ // Use linear-time version if applicable
+ if (m.size()==0 && c.size() > 0 &&
+ c instanceof SortedSet &&
+ m instanceof TreeMap) {
+ SortedSet<? extends E> set = (SortedSet<? extends E>) c;
+ TreeMap<E,Object> map = (TreeMap<E, Object>) m;
+ Comparator<?> cc = set.comparator();
+ Comparator<? super E> mc = map.comparator();
+ if (cc==mc || (cc != null && cc.equals(mc))) {
+ map.addAllForTreeSet(set, PRESENT);
+ return true;
+ }
+ }
+ return super.addAll(c);
+ }
+
+ /**
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException if {@code fromElement} or {@code toElement}
+ * is null and this set uses natural ordering, or its comparator
+ * does not permit null elements
+ * @throws IllegalArgumentException {@inheritDoc}
+ * @since 1.6
+ */
+ public NavigableSet<E> subSet(E fromElement, boolean fromInclusive,
+ E toElement, boolean toInclusive) {
+ return new TreeSet<>(m.subMap(fromElement, fromInclusive,
+ toElement, toInclusive));
+ }
+
+ /**
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException if {@code toElement} is null and
+ * this set uses natural ordering, or its comparator does
+ * not permit null elements
+ * @throws IllegalArgumentException {@inheritDoc}
+ * @since 1.6
+ */
+ public NavigableSet<E> headSet(E toElement, boolean inclusive) {
+ return new TreeSet<>(m.headMap(toElement, inclusive));
+ }
+
+ /**
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException if {@code fromElement} is null and
+ * this set uses natural ordering, or its comparator does
+ * not permit null elements
+ * @throws IllegalArgumentException {@inheritDoc}
+ * @since 1.6
+ */
+ public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
+ return new TreeSet<>(m.tailMap(fromElement, inclusive));
+ }
+
+ /**
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException if {@code fromElement} or
+ * {@code toElement} is null and this set uses natural ordering,
+ * or its comparator does not permit null elements
+ * @throws IllegalArgumentException {@inheritDoc}
+ */
+ public SortedSet<E> subSet(E fromElement, E toElement) {
+ return subSet(fromElement, true, toElement, false);
+ }
+
+ /**
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException if {@code toElement} is null
+ * and this set uses natural ordering, or its comparator does
+ * not permit null elements
+ * @throws IllegalArgumentException {@inheritDoc}
+ */
+ public SortedSet<E> headSet(E toElement) {
+ return headSet(toElement, false);
+ }
+
+ /**
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException if {@code fromElement} is null
+ * and this set uses natural ordering, or its comparator does
+ * not permit null elements
+ * @throws IllegalArgumentException {@inheritDoc}
+ */
+ public SortedSet<E> tailSet(E fromElement) {
+ return tailSet(fromElement, true);
+ }
+
+ public Comparator<? super E> comparator() {
+ return m.comparator();
+ }
+
+ /**
+ * @throws NoSuchElementException {@inheritDoc}
+ */
+ public E first() {
+ return m.firstKey();
+ }
+
+ /**
+ * @throws NoSuchElementException {@inheritDoc}
+ */
+ public E last() {
+ return m.lastKey();
+ }
+
+ // NavigableSet API methods
+
+ /**
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException if the specified element is null
+ * and this set uses natural ordering, or its comparator
+ * does not permit null elements
+ * @since 1.6
+ */
+ public E lower(E e) {
+ return m.lowerKey(e);
+ }
+
+ /**
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException if the specified element is null
+ * and this set uses natural ordering, or its comparator
+ * does not permit null elements
+ * @since 1.6
+ */
+ public E floor(E e) {
+ return m.floorKey(e);
+ }
+
+ /**
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException if the specified element is null
+ * and this set uses natural ordering, or its comparator
+ * does not permit null elements
+ * @since 1.6
+ */
+ public E ceiling(E e) {
+ return m.ceilingKey(e);
+ }
+
+ /**
+ * @throws ClassCastException {@inheritDoc}
+ * @throws NullPointerException if the specified element is null
+ * and this set uses natural ordering, or its comparator
+ * does not permit null elements
+ * @since 1.6
+ */
+ public E higher(E e) {
+ return m.higherKey(e);
+ }
+
+ /**
+ * @since 1.6
+ */
+ public E pollFirst() {
+ Map.Entry<E,?> e = m.pollFirstEntry();
+ return (e == null) ? null : e.getKey();
+ }
+
+ /**
+ * @since 1.6
+ */
+ public E pollLast() {
+ Map.Entry<E,?> e = m.pollLastEntry();
+ return (e == null) ? null : e.getKey();
+ }
+
+ /**
+ * Returns a shallow copy of this {@code TreeSet} instance. (The elements
+ * themselves are not cloned.)
+ *
+ * @return a shallow copy of this set
+ */
+ @SuppressWarnings("unchecked")
+ public Object clone() {
+ TreeSet<E> clone;
+ try {
+ clone = (TreeSet<E>) super.clone();
+ } catch (CloneNotSupportedException e) {
+ throw new InternalError(e);
+ }
+
+ clone.m = new TreeMap<>(m);
+ return clone;
+ }
+
+ /**
+ * Save the state of the {@code TreeSet} instance to a stream (that is,
+ * serialize it).
+ *
+ * @serialData Emits the comparator used to order this set, or
+ * {@code null} if it obeys its elements' natural ordering
+ * (Object), followed by the size of the set (the number of
+ * elements it contains) (int), followed by all of its
+ * elements (each an Object) in order (as determined by the
+ * set's Comparator, or by the elements' natural ordering if
+ * the set has no Comparator).
+ */
+ private void writeObject(java.io.ObjectOutputStream s)
+ throws java.io.IOException {
+ // Write out any hidden stuff
+ s.defaultWriteObject();
+
+ // Write out Comparator
+ s.writeObject(m.comparator());
+
+ // Write out size
+ s.writeInt(m.size());
+
+ // Write out all elements in the proper order.
+ for (E e : m.keySet())
+ s.writeObject(e);
+ }
+
+ /**
+ * Reconstitute the {@code TreeSet} instance from a stream (that is,
+ * deserialize it).
+ */
+ private void readObject(java.io.ObjectInputStream s)
+ throws java.io.IOException, ClassNotFoundException {
+ // Read in any hidden stuff
+ s.defaultReadObject();
+
+ // Read in Comparator
+ @SuppressWarnings("unchecked")
+ Comparator<? super E> c = (Comparator<? super E>) s.readObject();
+
+ // Create backing TreeMap
+ TreeMap<E,Object> tm = new TreeMap<>(c);
+ m = tm;
+
+ // Read in size
+ int size = s.readInt();
+
+ tm.readTreeSet(size, s, PRESENT);
+ }
+
+ /**
+ * Creates a <em><a href="Spliterator.html#binding">late-binding</a></em>
+ * and <em>fail-fast</em> {@link Spliterator} over the elements in this
+ * set.
+ *
+ * <p>The {@code Spliterator} reports {@link Spliterator#SIZED},
+ * {@link Spliterator#DISTINCT}, {@link Spliterator#SORTED}, and
+ * {@link Spliterator#ORDERED}. Overriding implementations should document
+ * the reporting of additional characteristic values.
+ *
+ * <p>The spliterator's comparator (see
+ * {@link java.util.Spliterator#getComparator()}) is {@code null} if
+ * the tree set's comparator (see {@link #comparator()}) is {@code null}.
+ * Otherwise, the spliterator's comparator is the same as or imposes the
+ * same total ordering as the tree set's comparator.
+ *
+ * @return a {@code Spliterator} over the elements in this set
+ * @since 1.8
+ */
+ public Spliterator<E> spliterator() {
+ return TreeMap.keySpliteratorFor(m);
+ }
+
+ private static final long serialVersionUID = -2479143000061671589L;
+}