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	/*
	* 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;

	/**
	* 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;
	static {
	try {
	MethodHandles.Lookup l = MethodHandles.lookup();
	VALUE = l.findVarHandle(AtomicBoolean.class, "value", int.class);
	} catch (ReflectiveOperationException e) {
	throw new ExceptionInInitializerError(e);
	}
	}

	private volatile int value;

	/**
	* Creates a new {@code AtomicBoolean} with the given initial value.
	*
	* @param initialValue the initial value
	*/
	public AtomicBoolean(boolean initialValue) {
	value = initialValue ? 1 : 0;
	}

	/**
	* 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;
	}

	/**
	* Returns the String representation of the current value.
	* @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 witness value, 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 witness value, 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 witness value, 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));
	}

	}

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