| /* |
| * 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); |
| } |
| |
| } |
