groovyx.gpars.dataflow.impl
[Java] Class SelectBase

java.lang.Object
  groovyx.gpars.dataflow.impl.SelectBase

@SuppressWarnings({"rawtypes", "RawUseOfParameterizedType"})
public final class SelectBase

The implementation of the core for all selects.

Authors:

Vaclav Pech Date: 29th Sep 2010

channels

private final java.util.List channels

disabledDFVs

private final boolean[] disabledDFVs

Since DataflowVariables should be only read once, they need to be disabled after selecting their value The array stores a boolean flag for each index, indicating, whether the channel/variable has been disabled

numberOfChannels

private final int numberOfChannels

pendingRequests

private final java.util.Collection pendingRequests

Unsatisfied requests for value, each holding a list of guards and a routine to invoke once a value is available

position

@SuppressWarnings({"UnsecureRandomNumberGeneration"})
private final java.util.Random position

SelectBase

public SelectBase(PGroup pGroup, java.util.List channels)

Stores the input channel and registers for the wheneverBound() event on each

Parameters:

pGroup - The group, the thread pool of which should be used for notification message handlers

channels - All the input channels to select on

boundNotification

@SuppressWarnings({"MethodOnlyUsedFromInnerClass"})
void boundNotification(int index, DataflowReadChannel channel)

Invoked by the SelectCallback instances, potentially concurrently to inform about new values being available for read from channels.

throws:

InterruptedException If the thread is interrupted during value retrieval from the channel

Parameters:

index - The index of the ready channel

channel - The channel itself

disableDFV

private void disableDFV(int currentPosition, DataflowReadChannel channel)

Sets the flag in the disabledDFVs array, if the channel is a DFV

Parameters:

currentPosition - The position to mark

channel - The channel being considered

doSelect

public void doSelect(int startIndex, SelectRequest selectRequest)

Invoked whenever the Select is asked for the next value. Depending on the supplied startIndex value it scans all input channels and reads the first one found, which currently has a value available for read. If no input channel is ready, the supplied SelectRequest instance is registered to be notified by the wheneverBound() channel listeners.

throws:

InterruptedException If the thread gets interrupted while reading messages from the channels

Parameters:

startIndex - The index of the channel to check first for available messages, -1 if start at a random position. Continue scanning by increasing the index, once the size is reached start from 0.

selectRequest - The request that holds the guards and expects a notification once a value is selected

Copyright © 2008–2012 Václav Pech. All Rights Reserved.