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, Cancellable

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

FutureForkJoin(int nrFinishFuturesSuccess, boolean cancelFuturesOnFinish, K... forks)
Create a future fork join object

FutureForkJoin(K... forks)
Facade if we expect everything to return successfully

Method Summary

List<K>	getCompleted() Returns a list of evaluated futures.
String	getFailedReason() The default failed reason is Unknown.
K	getLast() Returns the last evaluated future.
int	getSuccessCounter() Returns the number of successful finished futures

Methods inherited from class net.tomp2p.futures.BaseFutureImpl

addCancellation, addListener, addListener, await, await, awaitListeners, awaitUninterruptibly, awaitUninterruptibly, cancel, getType, isCompleted, isFailed, isSuccess, notifyListerenrs, removeListener, self, setCompletedAndNotify, setFailed, setFailed, setFailed, setFailed, setFailed

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

addCancellation, addListener, addListener, await, await, awaitListeners, awaitUninterruptibly, awaitUninterruptibly, getType, isCompleted, isFailed, isSuccess, removeListener, setFailed, setFailed, setFailed, setFailed, setFailed

Methods inherited from interface net.tomp2p.futures.Cancellable

cancel

Constructor Detail

FutureForkJoin

public FutureForkJoin(K... forks)

Facade if we expect everything to return successfully

Parameters:

forks - The futures

FutureForkJoin

public FutureForkJoin(int nrFinishFuturesSuccess,
                      boolean cancelFuturesOnFinish,
                      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 future array, that may contain null futures.

Method Detail

getFailedReason

public String getFailedReason()

Description copied from interface: BaseFuture

The default failed reason is Unknown.

Specified by:

getFailedReason in interface BaseFuture

Overrides:

getFailedReason in class BaseFutureImpl<FutureForkJoin<K extends BaseFuture>>

Returns:

Returns the reason why a future failed.

getLast

public K getLast()

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.

getCompleted

public List<K> getCompleted()

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

Returns:

A list of evaluated futures.

getSuccessCounter

public int getSuccessCounter()

Returns the number of successful finished futures

Returns:

The number of successful finished futures