edu.rice.hj.runtime.forkjoin

Class ParallelFuture<ValueType>

java.lang.Object

edu.rice.hj.runtime.forkjoin.ParallelFuture<ValueType>

Type Parameters:

ValueType - The type of the value to wrap

All Implemented Interfaces:

HjFuture<ValueType>

Direct Known Subclasses:

ParallelDataDrivenFuture

public class ParallelFuture<ValueType>
extends Object
implements HjFuture<ValueType>

A thread blocking implementation of HjFuture. It uses a java.util.concurrent.CountDownLatch to keep track of when the value becomes available.

Author:

Shams Imam (shams@rice.edu)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ParallelFuture.EventType
static class	ParallelFuture.ExecutionState

Nested classes/interfaces inherited from interface edu.rice.hj.api.HjFuture

HjFuture.CancelledException

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ParallelFuture() No-args Constructor.

Method Summary

Modifier and Type	Method and Description
protected void	attachListener(PropertyChangeListener changeListener) attachListener.
boolean	cancel() Attempts to cancel execution of this task.
static <ValueType> ParallelFuture<ValueType>	factory() Factory method.
boolean	failed() Return true if there was an exception while computing the value.
void	failed(Exception ex) Notifies that there was an exception while computing the result of the future.
ValueType	get() Returns the value wrapped in the future.
protected boolean	isCancelled()
protected boolean	markStart()
protected Runnable	preReleaseCallback()
void	put(ValueType newValue) Associates the specified value with the HjFuture.
boolean	resolved() Returns whether the future has been resolved, i.e. the value has been computed.
protected ValueType	retrieveValue()
ValueType	safeGet() Returns the value wrapped in the Future.
protected void	throwPutFailedException(ValueType newValue) throwPutFailedException.

Methods inherited from class java.lang.Object

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

Constructor Detail

ParallelFuture

protected ParallelFuture()

No-args Constructor.

Method Detail

factory

public static <ValueType> ParallelFuture<ValueType> factory()

Factory method.

Type Parameters:

ValueType - The type of the value to wrap

Returns:

a new instance of the future.

attachListener

protected final void attachListener(PropertyChangeListener changeListener)

attachListener.

Parameters:

changeListener - The listener to attach to the future. The listener may be synchronously triggered.

cancel

public boolean cancel()

Attempts to cancel execution of this task. If this task has not started when cancel is called, this task should never run its body. If the task has already started, then the task will not be interrupted and the task will run to completion.

Specified by:

cancel in interface HjFuture<ValueType>

Returns:

false if the task could not be cancelled, typically because it has already completed normally or is being executed; true otherwise

isCancelled

protected boolean isCancelled()

markStart

protected boolean markStart()

put

public final void put(ValueType newValue)

Associates the specified value with the HjFuture. This operation may fail if the single assignment property is violated.

Parameters:

newValue - The value to store into the future.

failed

public final void failed(Exception ex)

Notifies that there was an exception while computing the result of the future. Associates the specified Exception as the reason of failure while computing the result of the HjFuture. This operation may fail if the single assignment property is violated.

Parameters:

ex - The exception while computing the result of the future

throwPutFailedException

protected void throwPutFailedException(ValueType newValue)

throwPutFailedException.

Parameters:

newValue - The value attempted to put into the future

get

public ValueType get()
              throws SuspendableException

Returns the value wrapped in the future.

If the future task has not completed as yet, the task performing the get() operation blocks until the result of the future becomes available.

Specified by:

get in interface HjFuture<ValueType>

Returns:

The value wrapped in the future.

Throws:

SuspendableException

safeGet

public ValueType safeGet()

Returns the value wrapped in the Future.

It is illegal to perform a safeGet() operation on an empty Future (i.e. one that has not yet been resolved).

Specified by:

safeGet in interface HjFuture<ValueType>

Returns:

The value wrapped in the future.

preReleaseCallback

protected Runnable preReleaseCallback()

retrieveValue

protected ValueType retrieveValue()

resolved

public final boolean resolved()

Returns whether the future has been resolved, i.e. the value has been computed.

Specified by:

resolved in interface HjFuture<ValueType>

Returns:

whether the future has been resolved, i.e. the value has been computed.

failed

public boolean failed()

Return true if there was an exception while computing the value.

Specified by:

failed in interface HjFuture<ValueType>

Returns:

true if there was an exception while computing the value.