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AtomicBoolean (Java Platform SE 6) - JDK 5 Documentation v6.0, Java 2 SDK 英文文档

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java.util.concurrent.atomic
Class AtomicBoolean

java.lang.Object
  java.util.concurrent.atomic.AtomicBoolean

All Implemented Interfaces:

Serializable

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public class AtomicBoolean
extends Object
implements Serializable

A boolean value that may be updated atomically. See the java.util.concurrent.atomic package specification for description of the properties of atomic variables. 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

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

 

Method Summary
boolean	compareAndSet(boolean expect, boolean update)           Atomically sets the value to the given updated value if the current value == the expected value.
boolean	get()           Returns the current value.
boolean	getAndSet(boolean newValue)           Atomically sets to the given value and returns the previous value.
void	lazySet(boolean newValue)           Eventually sets to the given value.
void	set(boolean newValue)           Unconditionally sets to the given value.
String	toString()           Returns the String representation of the current value.
boolean	weakCompareAndSet(boolean expect, boolean update)           Atomically sets the value to the given updated value if the current value == the expected value.

 

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

 

Constructor Detail

AtomicBoolean

public AtomicBoolean(boolean initialValue)

Creates a new AtomicBoolean with the given initial value.

Parameters:

initialValue - the initial value

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AtomicBoolean

public AtomicBoolean()

Creates a new AtomicBoolean with initial value false.

Method Detail

get

public final boolean get()

Returns the current value.

Returns:

the current value

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compareAndSet

public final boolean compareAndSet(boolean expect,
                                   boolean update)

Atomically sets the value to the given updated value if the current value == the expected value.

Parameters:

expect - the expected value

update - the new value

Returns:

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

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weakCompareAndSet

public boolean weakCompareAndSet(boolean expect,
                                 boolean update)

Atomically sets the value to the given updated value if the current value == the expected value.

May fail spuriously and does not provide ordering guarantees, so is only rarely an appropriate alternative to compareAndSet.

Parameters:

expect - the expected value

update - the new value

Returns:

true if successful.

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set

public final void set(boolean newValue)

Unconditionally sets to the given value.

Parameters:

newValue - the new value

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lazySet

public final void lazySet(boolean newValue)

Eventually sets to the given value.

Parameters:

newValue - the new value

Since:

1.6

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getAndSet

public final boolean getAndSet(boolean newValue)

Atomically sets to the given value and returns the previous value.

Parameters:

newValue - the new value

Returns:

the previous value

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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.

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