net.tomp2p.futures

Class FutureForkJoin<K extends BaseFuture>

java.lang.Object

net.tomp2p.futures.BaseFutureImpl<FutureForkJoin<K>>

net.tomp2p.futures.FutureForkJoin<K>

Type Parameters:

K -

All Implemented Interfaces:

BaseFuture, Cancel

public class FutureForkJoin<K extends BaseFuture>
extends BaseFutureImpl<FutureForkJoin<K>>
implements BaseFuture

The key future for recursive loops. A first version with the fork-join framework did not reduce the code complexity significantly, thus I decided to write this class. The basic idea is that you can create parallel loops. For example in a routing process (loop to find closest peers), one starts to ask 3 peers in parallel, the first that returns result gets evaluated for new information about other peers, and a new peer is asked. If two peers finish, then two other peers are asked. Thus, we keep always 3 connections running until we get the result.

Author:

Thomas Bocek

Nested Class Summary

Nested classes/interfaces inherited from interface net.tomp2p.futures.BaseFuture

BaseFuture.FutureType

Field Summary

Fields inherited from class net.tomp2p.futures.BaseFutureImpl

completed, lock, reason, type

Constructor Summary

Constructors

Constructor and Description
FutureForkJoin(AtomicReferenceArray<K> forks) Facade if we expect everything to return successfully.
FutureForkJoin(int nrFinishFuturesSuccess, boolean cancelFuturesOnFinish, AtomicReferenceArray<K> forks) Create a future fork join object.

Method Summary

Methods

Modifier and Type	Method and Description
List<K>	completed() Returns a list of evaluated futures.
K	first()
FutureDone<Void>	futuresCompleted()
K	last() Returns the last evaluated future.
int	successCounter() Returns the number of successful finished futures.

Methods inherited from class net.tomp2p.futures.BaseFutureImpl

addCancel, addListener, addListener, await, await, awaitListeners, awaitListenersUninterruptibly, awaitUninterruptibly, awaitUninterruptibly, cancel, completedAndNotify, failed, failed, failed, failed, failed, failedReason, isCompleted, isFailed, isSuccess, notifyListeners, removeCancel, removeListener, self, self, type

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.tomp2p.futures.BaseFuture

addCancel, addListener, addListener, await, await, awaitListeners, awaitListenersUninterruptibly, awaitUninterruptibly, awaitUninterruptibly, failed, failed, failed, failed, failed, failedReason, isCompleted, isFailed, isSuccess, removeCancel, removeListener, type

Methods inherited from interface net.tomp2p.futures.Cancel

cancel

Constructor Detail

FutureForkJoin

public FutureForkJoin(AtomicReferenceArray<K> forks)

Facade if we expect everything to return successfully.

Parameters:

forks - The futures that can also be modified outside this class. If a future is finished the future in that array will be set to null. A future may be initially null, which is considered a failure.

FutureForkJoin

public FutureForkJoin(int nrFinishFuturesSuccess,
              boolean cancelFuturesOnFinish,
              AtomicReferenceArray<K> forks)

Create a future fork join object.

Parameters:

nrFinishFuturesSuccess - Is the number of futures that we expect to succeed.

cancelFuturesOnFinish - Tells use if we should cancel the remaining futures. For get() it makes sense to cancel, for store() it does not.

forks - The futures that can also be modified outside this class. If a future is finished the future in that array will be set to null. A future may be initially null, which is considered a failure.

Method Detail

last

public K last()

Returns the last evaluated future. This method may return null if an array with null values have been has been used.

Returns:

The last evaluated future.

first

public K first()

completed

public List<K> completed()

Returns a list of evaluated futures. The last completed future is the same as retrieved with last().

Returns:

A list of evaluated futures.

successCounter

public int successCounter()

Returns the number of successful finished futures.

Returns:

The number of successful finished futures

futuresCompleted

public FutureDone<Void> futuresCompleted()