com.yost.util
Class AtomicReferenceWithWait<T>

java.lang.Object
  com.yost.util.AtomicReferenceWithWait<T>

public class AtomicReferenceWithWait<T>
extends Object

An object reference that can be updated atomically, and which allows clients to wait for the value to change to suit their needs. Unlike AtomicReference,

• some methods of this class are specifically designed to block,
• there is no weakCompareAndSet method
• atomicity is achieved by synchronizing on a monitor lock object, (i.e., the implementation is not lock-free), and
• the monitor lock object can be set.

See the java.util.concurrent.atomic package specification.

Constructor Summary

AtomicReferenceWithWait()
Create a new AtomicReferenceWithWait with null initial value.

AtomicReferenceWithWait(T initialValue)
Create a new AtomicReferenceWithWait with the given initial value.

Method Summary

boolean	compareEqualsAndSet(T expect, T update) Atomically set the value to the given updated value if the current value equals the expected value.
boolean	compareIsAndSet(T expect, T update) Atomically set the value to the given updated value if the current value == the expected value.
boolean	compareIsNotAndSet(T expect, T update) Atomically set the value to the given updated value if the current value != the expected value.
boolean	compareNotEqualsAndSet(T expect, T update) Atomically set the value to the given updated value if the current value !equals the expected value.
T	get() Get the current value.
T	getAndSet(T newValue) Set to the given value and return the old value.
Object	getLockObject() Get the monitor lock object.
void	set(T newValue) Set to the given value.
void	setLockObject(Object newValue) Set the monitor lock object.
String	toString() Returns the String representation of the current value.
T	waitUntilValueEquals(T valueWanted) Wait until value equals the desired value, then return the current value.
T	waitUntilValueEqualsThenSet(T valueWanted, T newValue) Wait until value equals the desired object, then set to newValue and return the old value.
boolean	waitUntilValueIs(T objectReferenceWanted) Wait until value == the desired object, then return true if no waiting was necessary.
T	waitUntilValueIsNot(T objectReferenceNotWanted) Wait until value != the desired object, then return the current value.
T	waitUntilValueIsNotThenSet(T objectReferenceWanted, T newValue) Wait until value != the desired object, then set to newValue and return the old value.
boolean	waitUntilValueIsThenSet(T objectReferenceWanted, T newValue) Wait until value == the desired object, then set to newValue and return true if no waiting was necessary.
T	waitUntilValueNotEquals(T valueNotWanted) Wait until value !equals the desired value, then return the current value.
T	waitUntilValueNotEqualsThenSet(T valueWanted, T newValue) Wait until value not equals the desired object, then set to newValue and return the old value.

Methods inherited from class java.lang.Object

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

Constructor Detail

AtomicReferenceWithWait

public AtomicReferenceWithWait(T initialValue)

Create a new AtomicReferenceWithWait with the given initial value.

Parameters:

initialValue - the initial value

AtomicReferenceWithWait

public AtomicReferenceWithWait()

Create a new AtomicReferenceWithWait with null initial value.

Method Detail

get

public T get()

Get the current value.

Returns:

the current value

set

public void set(T newValue)

Set to the given value.

Parameters:

newValue - the new value

compareIsAndSet

public final boolean compareIsAndSet(T expect,
                                     T update)

Atomically set 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 current value was not equal to the expected value.

compareEqualsAndSet

public final boolean compareEqualsAndSet(T expect,
                                         T update)

Atomically set the value to the given updated value if the current value equals the expected value.

Parameters:

expect - the expected value

update - the new value

Returns:

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

compareIsNotAndSet

public final boolean compareIsNotAndSet(T expect,
                                        T update)

Atomically set 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 current value was not equal to the expected value.

compareNotEqualsAndSet

public final boolean compareNotEqualsAndSet(T expect,
                                            T update)

Atomically set the value to the given updated value if the current value !equals the expected value.

Parameters:

expect - the expected value

update - the new value

Returns:

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

getAndSet

public final T getAndSet(T newValue)

Set to the given value and return the old value.

Parameters:

newValue - the new value

Returns:

the previous value

waitUntilValueIs

public final boolean waitUntilValueIs(T objectReferenceWanted)
                               throws InterruptedException

Wait until value == the desired object, then return true if no waiting was necessary.

Parameters:

objectReferenceWanted - the desired object

Returns:

true if no waiting necessary

Throws:

InterruptedException

waitUntilValueEquals

public final T waitUntilValueEquals(T valueWanted)
                             throws InterruptedException

Wait until value equals the desired value, then return the current value.

Parameters:

valueWanted - the current value

Returns:

the current value

Throws:

InterruptedException

waitUntilValueIsNot

public final T waitUntilValueIsNot(T objectReferenceNotWanted)
                            throws InterruptedException

Wait until value != the desired object, then return the current value.

Parameters:

objectReferenceNotWanted - the undesired object

Returns:

the current value

Throws:

InterruptedException

waitUntilValueNotEquals

public T waitUntilValueNotEquals(T valueNotWanted)
                          throws InterruptedException

Wait until value !equals the desired value, then return the current value.

Parameters:

valueNotWanted - the undesired value

Returns:

the current value

Throws:

InterruptedException

waitUntilValueIsThenSet

public final boolean waitUntilValueIsThenSet(T objectReferenceWanted,
                                             T newValue)
                                      throws InterruptedException

Wait until value == the desired object, then set to newValue and return true if no waiting was necessary.

Parameters:

objectReferenceWanted - the desired object

newValue - the new value

Returns:

true if no waiting necessary

Throws:

InterruptedException

waitUntilValueEqualsThenSet

public final T waitUntilValueEqualsThenSet(T valueWanted,
                                           T newValue)
                                    throws InterruptedException

Wait until value equals the desired object, then set to newValue and return the old value.

Parameters:

valueWanted - the desired object

newValue - the new value

Returns:

the old value

Throws:

InterruptedException

waitUntilValueIsNotThenSet

public final T waitUntilValueIsNotThenSet(T objectReferenceWanted,
                                          T newValue)
                                   throws InterruptedException

Wait until value != the desired object, then set to newValue and return the old value.

Parameters:

objectReferenceWanted - the desired object

newValue - the new value

Returns:

the old value

Throws:

InterruptedException

waitUntilValueNotEqualsThenSet

public final T waitUntilValueNotEqualsThenSet(T valueWanted,
                                              T newValue)
                                       throws InterruptedException

Wait until value not equals the desired object, then set to newValue and return the old value.

Parameters:

valueWanted - the desired object

newValue - the new value

Returns:

the old value

Throws:

InterruptedException

getLockObject

public Object getLockObject()

Get the monitor lock object.

Returns:

the monitor lock object

setLockObject

public void setLockObject(Object newValue)

Set the monitor lock object.

Parameters:

newValue - the new monitor lock object

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