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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:

Constructor Summary

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

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)

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)

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

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https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/util/concurrent/atomic/AtomicBoolean.html