566 lines
20 KiB
Java
566 lines
20 KiB
Java
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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* This file is available under and governed by the GNU General Public
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* License version 2 only, as published by the Free Software Foundation.
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* However, the following notice accompanied the original version of this
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* file:
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*
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* Written by Doug Lea with assistance from members of JCP JSR-166
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* Expert Group and released to the public domain, as explained at
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* http://creativecommons.org/publicdomain/zero/1.0/
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*/
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package java.util.concurrent.atomic;
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import java.lang.invoke.MethodHandles;
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import java.lang.invoke.VarHandle;
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import java.util.function.LongBinaryOperator;
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import java.util.function.LongUnaryOperator;
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/**
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* A {@code long} array in which elements may be updated atomically.
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* See the {@link VarHandle} specification for descriptions of the
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* properties of atomic accesses.
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* @since 1.5
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* @author Doug Lea
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*/
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public class AtomicLongArray implements java.io.Serializable {
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private static final long serialVersionUID = -2308431214976778248L;
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private static final VarHandle AA
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= MethodHandles.arrayElementVarHandle(long[].class);
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private final long[] array;
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/**
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* Creates a new AtomicLongArray of the given length, with all
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* elements initially zero.
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*
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* @param length the length of the array
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*/
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public AtomicLongArray(int length) {
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array = new long[length];
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}
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/**
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* Creates a new AtomicLongArray with the same length as, and
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* all elements copied from, the given array.
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*
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* @param array the array to copy elements from
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* @throws NullPointerException if array is null
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*/
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public AtomicLongArray(long[] array) {
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// Visibility guaranteed by final field guarantees
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this.array = array.clone();
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}
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/**
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* Returns the length of the array.
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*
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* @return the length of the array
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*/
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public final int length() {
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return array.length;
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}
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/**
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* Returns the current value of the element at index {@code i},
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* with memory effects as specified by {@link VarHandle#getVolatile}.
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*
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* @param i the index
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* @return the current value
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*/
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public final long get(int i) {
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return (long)AA.getVolatile(array, i);
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}
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/**
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* Sets the element at index {@code i} to {@code newValue},
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* with memory effects as specified by {@link VarHandle#setVolatile}.
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*
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* @param i the index
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* @param newValue the new value
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*/
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public final void set(int i, long newValue) {
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AA.setVolatile(array, i, newValue);
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}
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/**
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* Sets the element at index {@code i} to {@code newValue},
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* with memory effects as specified by {@link VarHandle#setRelease}.
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*
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* @param i the index
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* @param newValue the new value
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* @since 1.6
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*/
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public final void lazySet(int i, long newValue) {
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AA.setRelease(array, i, newValue);
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}
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/**
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* Atomically sets the element at index {@code i} to {@code
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* newValue} and returns the old value,
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* with memory effects as specified by {@link VarHandle#getAndSet}.
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*
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* @param i the index
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* @param newValue the new value
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* @return the previous value
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*/
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public final long getAndSet(int i, long newValue) {
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return (long)AA.getAndSet(array, i, newValue);
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}
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/**
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* Atomically sets the element at index {@code i} to {@code newValue}
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* if the element's current value {@code == expectedValue},
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* with memory effects as specified by {@link VarHandle#compareAndSet}.
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*
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* @param i the index
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* @param expectedValue the expected value
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* @param newValue the new value
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* @return {@code true} if successful. False return indicates that
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* the actual value was not equal to the expected value.
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*/
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public final boolean compareAndSet(int i, long expectedValue, long newValue) {
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return AA.compareAndSet(array, i, expectedValue, newValue);
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}
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/**
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* Possibly atomically sets the element at index {@code i} to
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* {@code newValue} if the element's current value {@code == expectedValue},
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* with memory effects as specified by {@link VarHandle#weakCompareAndSetPlain}.
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*
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* @deprecated This method has plain memory effects but the method
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* name implies volatile memory effects (see methods such as
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* {@link #compareAndExchange} and {@link #compareAndSet}). To avoid
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* confusion over plain or volatile memory effects it is recommended that
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* the method {@link #weakCompareAndSetPlain} be used instead.
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*
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* @param i the index
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* @param expectedValue the expected value
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* @param newValue the new value
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* @return {@code true} if successful
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* @see #weakCompareAndSetPlain
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*/
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@Deprecated(since="9")
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public final boolean weakCompareAndSet(int i, long expectedValue, long newValue) {
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return AA.weakCompareAndSetPlain(array, i, expectedValue, newValue);
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}
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/**
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* Possibly atomically sets the element at index {@code i} to
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* {@code newValue} if the element's current value {@code == expectedValue},
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* with memory effects as specified by {@link VarHandle#weakCompareAndSetPlain}.
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*
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* @param i the index
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* @param expectedValue the expected value
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* @param newValue the new value
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* @return {@code true} if successful
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* @since 9
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*/
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public final boolean weakCompareAndSetPlain(int i, long expectedValue, long newValue) {
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return AA.weakCompareAndSetPlain(array, i, expectedValue, newValue);
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}
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/**
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* Atomically increments the value of the element at index {@code i},
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* with memory effects as specified by {@link VarHandle#getAndAdd}.
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*
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* <p>Equivalent to {@code getAndAdd(i, 1)}.
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*
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* @param i the index
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* @return the previous value
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*/
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public final long getAndIncrement(int i) {
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return (long)AA.getAndAdd(array, i, 1L);
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}
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/**
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* Atomically decrements the value of the element at index {@code i},
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* with memory effects as specified by {@link VarHandle#getAndAdd}.
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*
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* <p>Equivalent to {@code getAndAdd(i, -1)}.
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*
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* @param i the index
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* @return the previous value
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*/
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public final long getAndDecrement(int i) {
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return (long)AA.getAndAdd(array, i, -1L);
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}
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/**
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* Atomically adds the given value to the element at index {@code i},
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* with memory effects as specified by {@link VarHandle#getAndAdd}.
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*
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* @param i the index
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* @param delta the value to add
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* @return the previous value
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*/
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public final long getAndAdd(int i, long delta) {
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return (long)AA.getAndAdd(array, i, delta);
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}
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/**
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* Atomically increments the value of the element at index {@code i},
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* with memory effects as specified by {@link VarHandle#getAndAdd}.
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*
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* <p>Equivalent to {@code addAndGet(i, 1)}.
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*
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* @param i the index
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* @return the updated value
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*/
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public final long incrementAndGet(int i) {
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return (long)AA.getAndAdd(array, i, 1L) + 1L;
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}
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/**
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* Atomically decrements the value of the element at index {@code i},
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* with memory effects as specified by {@link VarHandle#getAndAdd}.
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*
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* <p>Equivalent to {@code addAndGet(i, -1)}.
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*
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* @param i the index
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* @return the updated value
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*/
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public final long decrementAndGet(int i) {
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return (long)AA.getAndAdd(array, i, -1L) - 1L;
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}
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/**
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* Atomically adds the given value to the element at index {@code i},
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* with memory effects as specified by {@link VarHandle#getAndAdd}.
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*
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* @param i the index
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* @param delta the value to add
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* @return the updated value
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*/
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public long addAndGet(int i, long delta) {
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return (long)AA.getAndAdd(array, i, delta) + delta;
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}
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/**
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* Atomically updates (with memory effects as specified by {@link
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* VarHandle#compareAndSet}) the element at index {@code i} with
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* the results of applying the given function, returning the
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* previous value. The function should be side-effect-free, since
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* it may be re-applied when attempted updates fail due to
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* contention among threads.
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*
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* @param i the index
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* @param updateFunction a side-effect-free function
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* @return the previous value
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* @since 1.8
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*/
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public final long getAndUpdate(int i, LongUnaryOperator updateFunction) {
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long prev = get(i), next = 0L;
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for (boolean haveNext = false;;) {
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if (!haveNext)
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next = updateFunction.applyAsLong(prev);
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if (weakCompareAndSetVolatile(i, prev, next))
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return prev;
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haveNext = (prev == (prev = get(i)));
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}
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}
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/**
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* Atomically updates (with memory effects as specified by {@link
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* VarHandle#compareAndSet}) the element at index {@code i} with
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* the results of applying the given function, returning the
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* updated value. The function should be side-effect-free, since it
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* may be re-applied when attempted updates fail due to contention
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* among threads.
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*
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* @param i the index
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* @param updateFunction a side-effect-free function
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* @return the updated value
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* @since 1.8
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*/
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public final long updateAndGet(int i, LongUnaryOperator updateFunction) {
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long prev = get(i), next = 0L;
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for (boolean haveNext = false;;) {
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if (!haveNext)
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next = updateFunction.applyAsLong(prev);
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if (weakCompareAndSetVolatile(i, prev, next))
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return next;
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haveNext = (prev == (prev = get(i)));
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}
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}
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/**
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* Atomically updates (with memory effects as specified by {@link
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* VarHandle#compareAndSet}) the element at index {@code i} with
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* the results of applying the given function to the current and
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* given values, returning the previous value. The function should
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* be side-effect-free, since it may be re-applied when attempted
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* updates fail due to contention among threads. The function is
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* applied with the current value of the element at index {@code i}
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* as its first argument, and the given update as the second
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* argument.
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*
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* @param i the index
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* @param x the update value
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* @param accumulatorFunction a side-effect-free function of two arguments
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* @return the previous value
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* @since 1.8
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*/
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public final long getAndAccumulate(int i, long x,
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LongBinaryOperator accumulatorFunction) {
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long prev = get(i), next = 0L;
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for (boolean haveNext = false;;) {
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if (!haveNext)
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next = accumulatorFunction.applyAsLong(prev, x);
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if (weakCompareAndSetVolatile(i, prev, next))
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return prev;
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haveNext = (prev == (prev = get(i)));
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}
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}
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/**
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* Atomically updates (with memory effects as specified by {@link
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* VarHandle#compareAndSet}) the element at index {@code i} with
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* the results of applying the given function to the current and
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* given values, returning the updated value. The function should
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* be side-effect-free, since it may be re-applied when attempted
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* updates fail due to contention among threads. The function is
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* applied with the current value of the element at index {@code i}
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* as its first argument, and the given update as the second
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* argument.
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*
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* @param i the index
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* @param x the update value
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* @param accumulatorFunction a side-effect-free function of two arguments
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* @return the updated value
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* @since 1.8
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*/
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public final long accumulateAndGet(int i, long x,
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LongBinaryOperator accumulatorFunction) {
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long prev = get(i), next = 0L;
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for (boolean haveNext = false;;) {
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if (!haveNext)
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next = accumulatorFunction.applyAsLong(prev, x);
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if (weakCompareAndSetVolatile(i, prev, next))
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return next;
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haveNext = (prev == (prev = get(i)));
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}
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}
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/**
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* Returns the String representation of the current values of array.
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* @return the String representation of the current values of array
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*/
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public String toString() {
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int iMax = array.length - 1;
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if (iMax == -1)
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return "[]";
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StringBuilder b = new StringBuilder();
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b.append('[');
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for (int i = 0; ; i++) {
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b.append(get(i));
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if (i == iMax)
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return b.append(']').toString();
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b.append(',').append(' ');
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}
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}
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// jdk9
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/**
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* Returns the current value of the element at index {@code i},
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* with memory semantics of reading as if the variable was declared
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* non-{@code volatile}.
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*
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* @param i the index
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* @return the value
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* @since 9
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*/
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public final long getPlain(int i) {
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return (long)AA.get(array, i);
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}
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/**
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* Sets the element at index {@code i} to {@code newValue},
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* with memory semantics of setting as if the variable was
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* declared non-{@code volatile} and non-{@code final}.
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*
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* @param i the index
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* @param newValue the new value
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* @since 9
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*/
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public final void setPlain(int i, long newValue) {
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AA.set(array, i, newValue);
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}
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/**
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* Returns the current value of the element at index {@code i},
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* with memory effects as specified by {@link VarHandle#getOpaque}.
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*
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* @param i the index
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* @return the value
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* @since 9
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*/
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public final long getOpaque(int i) {
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return (long)AA.getOpaque(array, i);
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}
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/**
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* Sets the element at index {@code i} to {@code newValue},
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* with memory effects as specified by {@link VarHandle#setOpaque}.
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*
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* @param i the index
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* @param newValue the new value
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* @since 9
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*/
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public final void setOpaque(int i, long newValue) {
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AA.setOpaque(array, i, newValue);
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}
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/**
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* Returns the current value of the element at index {@code i},
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* with memory effects as specified by {@link VarHandle#getAcquire}.
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*
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* @param i the index
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* @return the value
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* @since 9
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*/
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public final long getAcquire(int i) {
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return (long)AA.getAcquire(array, i);
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}
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|
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/**
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* 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
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*/
|
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public final void setRelease(int i, long newValue) {
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AA.setRelease(array, i, newValue);
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}
|
|
|
|
/**
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* 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
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|
*/
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|
public final long compareAndExchange(int i, long expectedValue, long newValue) {
|
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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
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|
*/
|
|
public final long compareAndExchangeAcquire(int i, long expectedValue, long newValue) {
|
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return (long)AA.compareAndExchangeAcquire(array, i, expectedValue, newValue);
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|
}
|
|
|
|
/**
|
|
* 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);
|
|
}
|
|
|
|
}
|