org.compass.core.util.backport.java.util.concurrent.atomic
Class AtomicReference

java.lang.Object
  org.compass.core.util.backport.java.util.concurrent.atomic.AtomicReference

All Implemented Interfaces:

Serializable

public class AtomicReference
extends Object
implements Serializable

An object reference that may be updated atomically. See the org.compass.core.util.backport.java.util.concurrent.atomic package specification for description of the properties of atomic variables.

Since:

1.5

Author:

Doug Lea

See Also:

Serialized Form

Constructor Summary

AtomicReference()
Creates a new AtomicReference with null initial value.

AtomicReference(Object initialValue)
Creates a new AtomicReference with the given initial value.

Method Summary

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

AtomicReference

public AtomicReference(Object initialValue)

Creates a new AtomicReference with the given initial value.

Parameters:

initialValue - the initial value

AtomicReference

public AtomicReference()

Creates a new AtomicReference with null initial value.

Method Detail

get

public final Object get()

Gets the current value.

Returns:

the current value

set

public final void set(Object newValue)

Sets to the given value.

Parameters:

newValue - the new value

lazySet

public final void lazySet(Object newValue)

Eventually sets to the given value.

Parameters:

newValue - the new value

Since:

1.6

compareAndSet

public final boolean compareAndSet(Object expect,
                                   Object 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.

weakCompareAndSet

public final boolean weakCompareAndSet(Object expect,
                                       Object update)

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

Parameters:

expect - the expected value

update - the new value

Returns:

true if successful.

getAndSet

public final Object getAndSet(Object newValue)

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

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.