Module java.base

Package java.util.concurrent.atomic

Class AtomicBoolean

java.lang.Object

java.util.concurrent.atomic.AtomicBoolean

All Implemented Interfaces:

Serializable

public class AtomicBoolean
extends Object
implements Serializable

A boolean value that may be updated atomically. See the VarHandle specification for descriptions of the properties of atomic accesses. An AtomicBoolean is used in applications such as atomically updated flags, and cannot be used as a replacement for a Boolean.

Since:

1.5

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
AtomicBoolean()	Creates a new AtomicBoolean with initial value false.
AtomicBoolean(boolean initialValue)	Creates a new AtomicBoolean with the given initial value.

Method Summary

Modifier and Type	Method	Description
final boolean	compareAndExchange(boolean expectedValue, boolean newValue)	Atomically sets the value to newValue if the current value, referred to as the witness value, == expectedValue, with memory effects as specified by VarHandle.compareAndExchange(java.lang.Object...).
final boolean	compareAndExchangeAcquire(boolean expectedValue, boolean newValue)	Atomically sets the value to newValue if the current value, referred to as the witness value, == expectedValue, with memory effects as specified by VarHandle.compareAndExchangeAcquire(java.lang.Object...).
final boolean	compareAndExchangeRelease(boolean expectedValue, boolean newValue)	Atomically sets the value to newValue if the current value, referred to as the witness value, == expectedValue, with memory effects as specified by VarHandle.compareAndExchangeRelease(java.lang.Object...).
final boolean	compareAndSet(boolean expectedValue, boolean newValue)	Atomically sets the value to newValue if the current value == expectedValue, with memory effects as specified by VarHandle.compareAndSet(java.lang.Object...).
final boolean	get()	Returns the current value, with memory effects as specified by VarHandle.getVolatile(java.lang.Object...).
final boolean	getAcquire()	Returns the current value, with memory effects as specified by VarHandle.getAcquire(java.lang.Object...).
final boolean	getAndSet(boolean newValue)	Atomically sets the value to newValue and returns the old value, with memory effects as specified by VarHandle.getAndSet(java.lang.Object...).
final boolean	getOpaque()	Returns the current value, with memory effects as specified by VarHandle.getOpaque(java.lang.Object...).
final boolean	getPlain()	Returns the current value, with memory semantics of reading as if the variable was declared non-volatile.
final void	lazySet(boolean newValue)	Sets the value to newValue, with memory effects as specified by VarHandle.setRelease(java.lang.Object...).
final void	set(boolean newValue)	Sets the value to newValue, with memory effects as specified by VarHandle.setVolatile(java.lang.Object...).
final void	setOpaque(boolean newValue)	Sets the value to newValue, with memory effects as specified by VarHandle.setOpaque(java.lang.Object...).
final void	setPlain(boolean newValue)	Sets the value to newValue, with memory semantics of setting as if the variable was declared non-volatile and non-final.
final void	setRelease(boolean newValue)	Sets the value to newValue, with memory effects as specified by VarHandle.setRelease(java.lang.Object...).
String	toString()	Returns the String representation of the current value.
boolean	weakCompareAndSet(boolean expectedValue, boolean newValue)	Deprecated. This method has plain memory effects but the method name implies volatile memory effects (see methods such as compareAndExchange(boolean, boolean) and compareAndSet(boolean, boolean)).
final boolean	weakCompareAndSetAcquire(boolean expectedValue, boolean newValue)	Possibly atomically sets the value to newValue if the current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetAcquire(java.lang.Object...).
boolean	weakCompareAndSetPlain(boolean expectedValue, boolean newValue)	Possibly atomically sets the value to newValue if the current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetPlain(java.lang.Object...).
final boolean	weakCompareAndSetRelease(boolean expectedValue, boolean newValue)	Possibly atomically sets the value to newValue if the current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetRelease(java.lang.Object...).
final boolean	weakCompareAndSetVolatile(boolean expectedValue, boolean newValue)	Possibly atomically sets the value to newValue if the current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSet(java.lang.Object...).

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

AtomicBoolean

public AtomicBoolean(boolean initialValue)

Creates a new AtomicBoolean with the given initial value.

Parameters:

initialValue - the initial value

AtomicBoolean

public AtomicBoolean()

Creates a new AtomicBoolean with initial value false.

Method Details

get

public final boolean get()

Returns the current value, with memory effects as specified by VarHandle.getVolatile(java.lang.Object...).

Returns:

the current value

compareAndSet

public final boolean compareAndSet(boolean expectedValue,
 boolean newValue)

Atomically sets the value to newValue if the current value == expectedValue, with memory effects as specified by VarHandle.compareAndSet(java.lang.Object...).

Parameters:

expectedValue - the expected value

newValue - the new value

Returns:

true if successful. False return indicates that the actual value was not equal to the expected value.

weakCompareAndSet

@Deprecated(since="9")
public boolean weakCompareAndSet(boolean expectedValue,
 boolean newValue)

Deprecated.

This method has plain memory effects but the method name implies volatile memory effects (see methods such as compareAndExchange(boolean, boolean) and compareAndSet(boolean, boolean)). To avoid confusion over plain or volatile memory effects it is recommended that the method weakCompareAndSetPlain(boolean, boolean) be used instead.

Possibly atomically sets the value to newValue if the current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetPlain(java.lang.Object...).

Parameters:

expectedValue - the expected value

newValue - the new value

Returns:

true if successful

See Also:

• weakCompareAndSetPlain(boolean, boolean)

weakCompareAndSetPlain

public boolean weakCompareAndSetPlain(boolean expectedValue,
 boolean newValue)

Possibly atomically sets the value to newValue if the current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetPlain(java.lang.Object...).

Parameters:

expectedValue - the expected value

newValue - the new value

Returns:

true if successful

Since:

9

set

public final void set(boolean newValue)

Sets the value to newValue, with memory effects as specified by VarHandle.setVolatile(java.lang.Object...).

Parameters:

newValue - the new value

lazySet

public final void lazySet(boolean newValue)

Sets the value to newValue, with memory effects as specified by VarHandle.setRelease(java.lang.Object...).

Parameters:

newValue - the new value

Since:

1.6

getAndSet

public final boolean getAndSet(boolean newValue)

Atomically sets the value to newValue and returns the old value, with memory effects as specified by VarHandle.getAndSet(java.lang.Object...).

Parameters:

newValue - the new value

Returns:

the previous value

toString

public String toString()

Returns the String representation of the current value.

Overrides:

toString in class Object

Returns:

the String representation of the current value

getPlain

public final boolean getPlain()

Returns the current value, with memory semantics of reading as if the variable was declared non-volatile.

Returns:

the value

Since:

9

setPlain

public final void setPlain(boolean newValue)

Sets the value to newValue, with memory semantics of setting as if the variable was declared non-volatile and non-final.

Parameters:

newValue - the new value

Since:

9

getOpaque

public final boolean getOpaque()

Returns the current value, with memory effects as specified by VarHandle.getOpaque(java.lang.Object...).

Returns:

the value

Since:

9

setOpaque

public final void setOpaque(boolean newValue)

Sets the value to newValue, with memory effects as specified by VarHandle.setOpaque(java.lang.Object...).

Parameters:

newValue - the new value

Since:

9

getAcquire

public final boolean getAcquire()

Returns the current value, with memory effects as specified by VarHandle.getAcquire(java.lang.Object...).

Returns:

the value

Since:

9

setRelease

public final void setRelease(boolean newValue)

Sets the value to newValue, with memory effects as specified by VarHandle.setRelease(java.lang.Object...).

Parameters:

newValue - the new value

Since:

9

compareAndExchange

public final boolean compareAndExchange(boolean expectedValue,
 boolean newValue)

Atomically sets the value to newValue if the current value, referred to as the witness value, == expectedValue, with memory effects as specified by VarHandle.compareAndExchange(java.lang.Object...).

Parameters:

expectedValue - the expected value

newValue - the new value

Returns:

the witness value, which will be the same as the expected value if successful

Since:

9

compareAndExchangeAcquire

public final boolean compareAndExchangeAcquire(boolean expectedValue,
 boolean newValue)

Atomically sets the value to newValue if the current value, referred to as the witness value, == expectedValue, with memory effects as specified by VarHandle.compareAndExchangeAcquire(java.lang.Object...).

Parameters:

expectedValue - the expected value

newValue - the new value

Returns:

the witness value, which will be the same as the expected value if successful

Since:

9

compareAndExchangeRelease

public final boolean compareAndExchangeRelease(boolean expectedValue,
 boolean newValue)

Atomically sets the value to newValue if the current value, referred to as the witness value, == expectedValue, with memory effects as specified by VarHandle.compareAndExchangeRelease(java.lang.Object...).

Parameters:

expectedValue - the expected value

newValue - the new value

Returns:

the witness value, which will be the same as the expected value if successful

Since:

9

weakCompareAndSetVolatile

public final boolean weakCompareAndSetVolatile(boolean expectedValue,
 boolean newValue)

Possibly atomically sets the value to newValue if the current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSet(java.lang.Object...).

Parameters:

expectedValue - the expected value

newValue - the new value

Returns:

true if successful

Since:

9

weakCompareAndSetAcquire

public final boolean weakCompareAndSetAcquire(boolean expectedValue,
 boolean newValue)

Possibly atomically sets the value to newValue if the current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetAcquire(java.lang.Object...).

Parameters:

expectedValue - the expected value

newValue - the new value

Returns:

true if successful

Since:

9

weakCompareAndSetRelease

public final boolean weakCompareAndSetRelease(boolean expectedValue,
 boolean newValue)

Possibly atomically sets the value to newValue if the current value == expectedValue, with memory effects as specified by VarHandle.weakCompareAndSetRelease(java.lang.Object...).

Parameters:

expectedValue - the expected value

newValue - the new value

Returns:

true if successful

Since:

9