| /* | |
| * 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 jdk.internal.invoke.MhUtil; | |
| import java.lang.invoke.MethodHandles; | |
| import java.lang.invoke.VarHandle; | |
| /** | |
| * A {@code boolean} value that may be updated atomically. See the | |
| * {@link VarHandle} specification for descriptions of the properties | |
| * of atomic accesses. An {@code AtomicBoolean} is used in | |
| * applications such as atomically updated flags, and cannot be used | |
| * as a replacement for a {@link java.lang.Boolean}. | |
| * | |
| * @since 1.5 | |
| * @author Doug Lea | |
| */ | |
| public class AtomicBoolean implements java.io.Serializable { | |
| private static final long serialVersionUID = 4654671469794556979L; | |
| private static final VarHandle VALUE = MhUtil.findVarHandle( | |
| MethodHandles.lookup(), "value", int.class); | |
| /** @serial */ | |
| private volatile int value; | |
| /** | |
| * Creates a new {@code AtomicBoolean} with the given initial value. | |
| * | |
| * @param initialValue the initial value | |
| */ | |
| public AtomicBoolean(boolean initialValue) { | |
| if (initialValue) | |
| value = 1; | |
| } | |
| /** | |
| * Creates a new {@code AtomicBoolean} with initial value {@code false}. | |
| */ | |
| public AtomicBoolean() { | |
| } | |
| /** | |
| * Returns the current value, | |
| * with memory effects as specified by {@link VarHandle#getVolatile}. | |
| * | |
| * @return the current value | |
| */ | |
| public final boolean get() { | |
| return value != 0; | |
| } | |
| /** | |
| * Atomically sets the value to {@code newValue} | |
| * if the current value {@code == expectedValue}, | |
| * with memory effects as specified by {@link VarHandle#compareAndSet}. | |
| * | |
| * @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(boolean expectedValue, boolean newValue) { | |
| return VALUE.compareAndSet(this, | |
| (expectedValue ? 1 : 0), | |
| (newValue ? 1 : 0)); | |
| } | |
| /** | |
| * Possibly atomically sets the value to {@code newValue} | |
| * if the 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 expectedValue the expected value | |
| * @param newValue the new value | |
| * @return {@code true} if successful | |
| * @see #weakCompareAndSetPlain | |
| */ | |
| @Deprecated(since="9") | |
| public boolean weakCompareAndSet(boolean expectedValue, boolean newValue) { | |
| return VALUE.weakCompareAndSetPlain(this, | |
| (expectedValue ? 1 : 0), | |
| (newValue ? 1 : 0)); | |
| } | |
| /** | |
| * Possibly atomically sets the value to {@code newValue} | |
| * if the current value {@code == expectedValue}, | |
| * with memory effects as specified by {@link VarHandle#weakCompareAndSetPlain}. | |
| * | |
| * @param expectedValue the expected value | |
| * @param newValue the new value | |
| * @return {@code true} if successful | |
| * @since 9 | |
| */ | |
| public boolean weakCompareAndSetPlain(boolean expectedValue, boolean newValue) { | |
| return VALUE.weakCompareAndSetPlain(this, | |
| (expectedValue ? 1 : 0), | |
| (newValue ? 1 : 0)); | |
| } | |
| /** | |
| * Sets the value to {@code newValue}, | |
| * with memory effects as specified by {@link VarHandle#setVolatile}. | |
| * | |
| * @param newValue the new value | |
| */ | |
| public final void set(boolean newValue) { | |
| value = newValue ? 1 : 0; | |
| } | |
| /** | |
| * Sets the value to {@code newValue}, | |
| * with memory effects as specified by {@link VarHandle#setRelease}. | |
| * | |
| * @param newValue the new value | |
| * @since 1.6 | |
| */ | |
| public final void lazySet(boolean newValue) { | |
| VALUE.setRelease(this, (newValue ? 1 : 0)); | |
| } | |
| /** | |
| * Atomically sets the value to {@code newValue} and returns the old value, | |
| * with memory effects as specified by {@link VarHandle#getAndSet}. | |
| * | |
| * @param newValue the new value | |
| * @return the previous value | |
| */ | |
| public final boolean getAndSet(boolean newValue) { | |
| return (int)VALUE.getAndSet(this, (newValue ? 1 : 0)) != 0; | |
| } | |
| /** | |
| * {@return the String representation of the current value} | |
| */ | |
| public String toString() { | |
| return Boolean.toString(get()); | |
| } | |
| // jdk9 | |
| /** | |
| * Returns the current value, with memory semantics of reading as | |
| * if the variable was declared non-{@code volatile}. | |
| * | |
| * @return the value | |
| * @since 9 | |
| */ | |
| public final boolean getPlain() { | |
| return (int)VALUE.get(this) != 0; | |
| } | |
| /** | |
| * Sets the value to {@code newValue}, with memory semantics | |
| * of setting as if the variable was declared non-{@code volatile} | |
| * and non-{@code final}. | |
| * | |
| * @param newValue the new value | |
| * @since 9 | |
| */ | |
| public final void setPlain(boolean newValue) { | |
| VALUE.set(this, newValue ? 1 : 0); | |
| } | |
| /** | |
| * Returns the current value, | |
| * with memory effects as specified by {@link VarHandle#getOpaque}. | |
| * | |
| * @return the value | |
| * @since 9 | |
| */ | |
| public final boolean getOpaque() { | |
| return (int)VALUE.getOpaque(this) != 0; | |
| } | |
| /** | |
| * Sets the value to {@code newValue}, | |
| * with memory effects as specified by {@link VarHandle#setOpaque}. | |
| * | |
| * @param newValue the new value | |
| * @since 9 | |
| */ | |
| public final void setOpaque(boolean newValue) { | |
| VALUE.setOpaque(this, newValue ? 1 : 0); | |
| } | |
| /** | |
| * Returns the current value, | |
| * with memory effects as specified by {@link VarHandle#getAcquire}. | |
| * | |
| * @return the value | |
| * @since 9 | |
| */ | |
| public final boolean getAcquire() { | |
| return (int)VALUE.getAcquire(this) != 0; | |
| } | |
| /** | |
| * Sets the value to {@code newValue}, | |
| * with memory effects as specified by {@link VarHandle#setRelease}. | |
| * | |
| * @param newValue the new value | |
| * @since 9 | |
| */ | |
| public final void setRelease(boolean newValue) { | |
| VALUE.setRelease(this, newValue ? 1 : 0); | |
| } | |
| /** | |
| * Atomically sets the value to {@code newValue} if the current value, | |
| * referred to as the <em>witness value</em>, {@code == expectedValue}, | |
| * with memory effects as specified by | |
| * {@link VarHandle#compareAndExchange}. | |
| * | |
| * @param expectedValue the expected value | |
| * @param newValue the new value | |
| * @return the <em>witness value</em>, which will be the same as the | |
| * expected value if successful | |
| * @since 9 | |
| */ | |
| public final boolean compareAndExchange(boolean expectedValue, boolean newValue) { | |
| return (int)VALUE.compareAndExchange(this, | |
| (expectedValue ? 1 : 0), | |
| (newValue ? 1 : 0)) != 0; | |
| } | |
| /** | |
| * Atomically sets the value to {@code newValue} if the current value, | |
| * referred to as the <em>witness value</em>, {@code == expectedValue}, | |
| * with memory effects as specified by | |
| * {@link VarHandle#compareAndExchangeAcquire}. | |
| * | |
| * @param expectedValue the expected value | |
| * @param newValue the new value | |
| * @return the <em>witness value</em>, which will be the same as the | |
| * expected value if successful | |
| * @since 9 | |
| */ | |
| public final boolean compareAndExchangeAcquire(boolean expectedValue, boolean newValue) { | |
| return (int)VALUE.compareAndExchangeAcquire(this, | |
| (expectedValue ? 1 : 0), | |
| (newValue ? 1 : 0)) != 0; | |
| } | |
| /** | |
| * Atomically sets the value to {@code newValue} if the current value, | |
| * referred to as the <em>witness value</em>, {@code == expectedValue}, | |
| * with memory effects as specified by | |
| * {@link VarHandle#compareAndExchangeRelease}. | |
| * | |
| * @param expectedValue the expected value | |
| * @param newValue the new value | |
| * @return the <em>witness value</em>, which will be the same as the | |
| * expected value if successful | |
| * @since 9 | |
| */ | |
| public final boolean compareAndExchangeRelease(boolean expectedValue, boolean newValue) { | |
| return (int)VALUE.compareAndExchangeRelease(this, | |
| (expectedValue ? 1 : 0), | |
| (newValue ? 1 : 0)) != 0; | |
| } | |
| /** | |
| * Possibly atomically sets the value to {@code newValue} if the current | |
| * value {@code == expectedValue}, | |
| * with memory effects as specified by | |
| * {@link VarHandle#weakCompareAndSet}. | |
| * | |
| * @param expectedValue the expected value | |
| * @param newValue the new value | |
| * @return {@code true} if successful | |
| * @since 9 | |
| */ | |
| public final boolean weakCompareAndSetVolatile(boolean expectedValue, boolean newValue) { | |
| return VALUE.weakCompareAndSet(this, | |
| (expectedValue ? 1 : 0), | |
| (newValue ? 1 : 0)); | |
| } | |
| /** | |
| * Possibly atomically sets the value to {@code newValue} if the current | |
| * value {@code == expectedValue}, | |
| * with memory effects as specified by | |
| * {@link VarHandle#weakCompareAndSetAcquire}. | |
| * | |
| * @param expectedValue the expected value | |
| * @param newValue the new value | |
| * @return {@code true} if successful | |
| * @since 9 | |
| */ | |
| public final boolean weakCompareAndSetAcquire(boolean expectedValue, boolean newValue) { | |
| return VALUE.weakCompareAndSetAcquire(this, | |
| (expectedValue ? 1 : 0), | |
| (newValue ? 1 : 0)); | |
| } | |
| /** | |
| * Possibly atomically sets the value to {@code newValue} if the current | |
| * value {@code == expectedValue}, | |
| * with memory effects as specified by | |
| * {@link VarHandle#weakCompareAndSetRelease}. | |
| * | |
| * @param expectedValue the expected value | |
| * @param newValue the new value | |
| * @return {@code true} if successful | |
| * @since 9 | |
| */ | |
| public final boolean weakCompareAndSetRelease(boolean expectedValue, boolean newValue) { | |
| return VALUE.weakCompareAndSetRelease(this, | |
| (expectedValue ? 1 : 0), | |
| (newValue ? 1 : 0)); | |
| } | |
| } |