src/java.base/share/classes/java/util/concurrent/atomic/AtomicLongArray.java
changeset 47216 71c04702a3d5
parent 45637 9e0c80381e32
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/util/concurrent/atomic/AtomicLongArray.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,565 @@
+/*
+ * 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.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file:
+ *
+ * Written by Doug Lea with assistance from members of JCP JSR-166
+ * Expert Group and released to the public domain, as explained at
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+package java.util.concurrent.atomic;
+
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.VarHandle;
+import java.util.function.LongBinaryOperator;
+import java.util.function.LongUnaryOperator;
+
+/**
+ * A {@code long} array in which elements may be updated atomically.
+ * See the {@link VarHandle} specification for descriptions of the
+ * properties of atomic accesses.
+ * @since 1.5
+ * @author Doug Lea
+ */
+public class AtomicLongArray implements java.io.Serializable {
+    private static final long serialVersionUID = -2308431214976778248L;
+    private static final VarHandle AA
+        = MethodHandles.arrayElementVarHandle(long[].class);
+    private final long[] array;
+
+    /**
+     * Creates a new AtomicLongArray of the given length, with all
+     * elements initially zero.
+     *
+     * @param length the length of the array
+     */
+    public AtomicLongArray(int length) {
+        array = new long[length];
+    }
+
+    /**
+     * Creates a new AtomicLongArray with the same length as, and
+     * all elements copied from, the given array.
+     *
+     * @param array the array to copy elements from
+     * @throws NullPointerException if array is null
+     */
+    public AtomicLongArray(long[] array) {
+        // Visibility guaranteed by final field guarantees
+        this.array = array.clone();
+    }
+
+    /**
+     * Returns the length of the array.
+     *
+     * @return the length of the array
+     */
+    public final int length() {
+        return array.length;
+    }
+
+    /**
+     * Returns the current value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getVolatile}.
+     *
+     * @param i the index
+     * @return the current value
+     */
+    public final long get(int i) {
+        return (long)AA.getVolatile(array, i);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setVolatile}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     */
+    public final void set(int i, long newValue) {
+        AA.setVolatile(array, i, newValue);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @since 1.6
+     */
+    public final void lazySet(int i, long newValue) {
+        AA.setRelease(array, i, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code
+     * newValue} and returns the old value,
+     * with memory effects as specified by {@link VarHandle#getAndSet}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @return the previous value
+     */
+    public final long getAndSet(int i, long newValue) {
+        return (long)AA.getAndSet(array, i, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#compareAndSet}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful. False return indicates that
+     * the actual value was not equal to the expected value.
+     */
+    public final boolean compareAndSet(int i, long expectedValue, long newValue) {
+        return AA.compareAndSet(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#weakCompareAndSetPlain}.
+     *
+     * @deprecated This method has plain memory effects but the method
+     * name implies volatile memory effects (see methods such as
+     * {@link #compareAndExchange} and {@link #compareAndSet}).  To avoid
+     * confusion over plain or volatile memory effects it is recommended that
+     * the method {@link #weakCompareAndSetPlain} be used instead.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @see #weakCompareAndSetPlain
+     */
+    @Deprecated(since="9")
+    public final boolean weakCompareAndSet(int i, long expectedValue, long newValue) {
+        return AA.weakCompareAndSetPlain(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by {@link VarHandle#weakCompareAndSetPlain}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetPlain(int i, long expectedValue, long newValue) {
+        return AA.weakCompareAndSetPlain(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically increments the value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * <p>Equivalent to {@code getAndAdd(i, 1)}.
+     *
+     * @param i the index
+     * @return the previous value
+     */
+    public final long getAndIncrement(int i) {
+        return (long)AA.getAndAdd(array, i, 1L);
+    }
+
+    /**
+     * Atomically decrements the value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * <p>Equivalent to {@code getAndAdd(i, -1)}.
+     *
+     * @param i the index
+     * @return the previous value
+     */
+    public final long getAndDecrement(int i) {
+        return (long)AA.getAndAdd(array, i, -1L);
+    }
+
+    /**
+     * Atomically adds the given value to the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * @param i the index
+     * @param delta the value to add
+     * @return the previous value
+     */
+    public final long getAndAdd(int i, long delta) {
+        return (long)AA.getAndAdd(array, i, delta);
+    }
+
+    /**
+     * Atomically increments the value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * <p>Equivalent to {@code addAndGet(i, 1)}.
+     *
+     * @param i the index
+     * @return the updated value
+     */
+    public final long incrementAndGet(int i) {
+        return (long)AA.getAndAdd(array, i, 1L) + 1L;
+    }
+
+    /**
+     * Atomically decrements the value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * <p>Equivalent to {@code addAndGet(i, -1)}.
+     *
+     * @param i the index
+     * @return the updated value
+     */
+    public final long decrementAndGet(int i) {
+        return (long)AA.getAndAdd(array, i, -1L) - 1L;
+    }
+
+    /**
+     * Atomically adds the given value to the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAndAdd}.
+     *
+     * @param i the index
+     * @param delta the value to add
+     * @return the updated value
+     */
+    public long addAndGet(int i, long delta) {
+        return (long)AA.getAndAdd(array, i, delta) + delta;
+    }
+
+    /**
+     * Atomically updates (with memory effects as specified by {@link
+     * VarHandle#compareAndSet}) the element at index {@code i} with
+     * the results of applying the given function, returning the
+     * previous value. The function should be side-effect-free, since
+     * it may be re-applied when attempted updates fail due to
+     * contention among threads.
+     *
+     * @param i the index
+     * @param updateFunction a side-effect-free function
+     * @return the previous value
+     * @since 1.8
+     */
+    public final long getAndUpdate(int i, LongUnaryOperator updateFunction) {
+        long prev = get(i), next = 0L;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.applyAsLong(prev);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return prev;
+            haveNext = (prev == (prev = get(i)));
+        }
+    }
+
+    /**
+     * Atomically updates (with memory effects as specified by {@link
+     * VarHandle#compareAndSet}) the element at index {@code i} with
+     * the results of applying the given function, returning the
+     * updated value. The function should be side-effect-free, since it
+     * may be re-applied when attempted updates fail due to contention
+     * among threads.
+     *
+     * @param i the index
+     * @param updateFunction a side-effect-free function
+     * @return the updated value
+     * @since 1.8
+     */
+    public final long updateAndGet(int i, LongUnaryOperator updateFunction) {
+        long prev = get(i), next = 0L;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = updateFunction.applyAsLong(prev);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return next;
+            haveNext = (prev == (prev = get(i)));
+        }
+    }
+
+    /**
+     * Atomically updates (with memory effects as specified by {@link
+     * VarHandle#compareAndSet}) the element at index {@code i} with
+     * the results of applying the given function to the current and
+     * given values, returning the previous value. The function should
+     * be side-effect-free, since it may be re-applied when attempted
+     * updates fail due to contention among threads.  The function is
+     * applied with the current value of the element at index {@code i}
+     * as its first argument, and the given update as the second
+     * argument.
+     *
+     * @param i the index
+     * @param x the update value
+     * @param accumulatorFunction a side-effect-free function of two arguments
+     * @return the previous value
+     * @since 1.8
+     */
+    public final long getAndAccumulate(int i, long x,
+                                      LongBinaryOperator accumulatorFunction) {
+        long prev = get(i), next = 0L;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.applyAsLong(prev, x);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return prev;
+            haveNext = (prev == (prev = get(i)));
+        }
+    }
+
+    /**
+     * Atomically updates (with memory effects as specified by {@link
+     * VarHandle#compareAndSet}) the element at index {@code i} with
+     * the results of applying the given function to the current and
+     * given values, returning the updated value. The function should
+     * be side-effect-free, since it may be re-applied when attempted
+     * updates fail due to contention among threads.  The function is
+     * applied with the current value of the element at index {@code i}
+     * as its first argument, and the given update as the second
+     * argument.
+     *
+     * @param i the index
+     * @param x the update value
+     * @param accumulatorFunction a side-effect-free function of two arguments
+     * @return the updated value
+     * @since 1.8
+     */
+    public final long accumulateAndGet(int i, long x,
+                                      LongBinaryOperator accumulatorFunction) {
+        long prev = get(i), next = 0L;
+        for (boolean haveNext = false;;) {
+            if (!haveNext)
+                next = accumulatorFunction.applyAsLong(prev, x);
+            if (weakCompareAndSetVolatile(i, prev, next))
+                return next;
+            haveNext = (prev == (prev = get(i)));
+        }
+    }
+
+    /**
+     * Returns the String representation of the current values of array.
+     * @return the String representation of the current values of array
+     */
+    public String toString() {
+        int iMax = array.length - 1;
+        if (iMax == -1)
+            return "[]";
+
+        StringBuilder b = new StringBuilder();
+        b.append('[');
+        for (int i = 0; ; i++) {
+            b.append(get(i));
+            if (i == iMax)
+                return b.append(']').toString();
+            b.append(',').append(' ');
+        }
+    }
+
+    // jdk9
+
+    /**
+     * Returns the current value of the element at index {@code i},
+     * with memory semantics of reading as if the variable was declared
+     * non-{@code volatile}.
+     *
+     * @param i the index
+     * @return the value
+     * @since 9
+     */
+    public final long getPlain(int i) {
+        return (long)AA.get(array, i);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory semantics of setting as if the variable was
+     * declared non-{@code volatile} and non-{@code final}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setPlain(int i, long newValue) {
+        AA.set(array, i, newValue);
+    }
+
+    /**
+     * Returns the current value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getOpaque}.
+     *
+     * @param i the index
+     * @return the value
+     * @since 9
+     */
+    public final long getOpaque(int i) {
+        return (long)AA.getOpaque(array, i);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setOpaque}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setOpaque(int i, long newValue) {
+        AA.setOpaque(array, i, newValue);
+    }
+
+    /**
+     * Returns the current value of the element at index {@code i},
+     * with memory effects as specified by {@link VarHandle#getAcquire}.
+     *
+     * @param i the index
+     * @return the value
+     * @since 9
+     */
+    public final long getAcquire(int i) {
+        return (long)AA.getAcquire(array, i);
+    }
+
+    /**
+     * Sets the element at index {@code i} to {@code newValue},
+     * with memory effects as specified by {@link VarHandle#setRelease}.
+     *
+     * @param i the index
+     * @param newValue the new value
+     * @since 9
+     */
+    public final void setRelease(int i, long newValue) {
+        AA.setRelease(array, i, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value, referred to as the <em>witness
+     * value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchange}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final long compareAndExchange(int i, long expectedValue, long newValue) {
+        return (long)AA.compareAndExchange(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value, referred to as the <em>witness
+     * value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeAcquire}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final long compareAndExchangeAcquire(int i, long expectedValue, long newValue) {
+        return (long)AA.compareAndExchangeAcquire(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Atomically sets the element at index {@code i} to {@code newValue}
+     * if the element's current value, referred to as the <em>witness
+     * value</em>, {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#compareAndExchangeRelease}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return the witness value, which will be the same as the
+     * expected value if successful
+     * @since 9
+     */
+    public final long compareAndExchangeRelease(int i, long expectedValue, long newValue) {
+        return (long)AA.compareAndExchangeRelease(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSet}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetVolatile(int i, long expectedValue, long newValue) {
+        return AA.weakCompareAndSet(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetAcquire}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetAcquire(int i, long expectedValue, long newValue) {
+        return AA.weakCompareAndSetAcquire(array, i, expectedValue, newValue);
+    }
+
+    /**
+     * Possibly atomically sets the element at index {@code i} to
+     * {@code newValue} if the element's current value {@code == expectedValue},
+     * with memory effects as specified by
+     * {@link VarHandle#weakCompareAndSetRelease}.
+     *
+     * @param i the index
+     * @param expectedValue the expected value
+     * @param newValue the new value
+     * @return {@code true} if successful
+     * @since 9
+     */
+    public final boolean weakCompareAndSetRelease(int i, long expectedValue, long newValue) {
+        return AA.weakCompareAndSetRelease(array, i, expectedValue, newValue);
+    }
+
+}