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groovyx.gpars.dataflow
[Java] Class Select

java.lang.Object
  groovyx.gpars.dataflow.Select

@SuppressWarnings({"MethodNamesDifferingOnlyByCase"})
public class Select
extends java.lang.Object

A Select allows the user to select a value from multiple channels, which have a value available for read at the moment. It can either pick a channel randomly, when using the plain select method, or with precedence towards channels with lower position indexes, when the prioritySelect method is used. If a value is not available immediately in any of the channels, Select will wait for the first value to arrive in any of the channels.

Both 'select' and 'prioritySelect' methods come in two flavours - blocking, which wait till a value is available in a channel, and messaging, which send out a message to the specified message handler, as soon as a message is available. Optionally, all methods allow the user to specify a boolean mask, assigning each select 's input channel a flag indicating, whether it should be included in the select operation. This is useful when handling state to selectively block some inputs in some states.

Authors:
Vaclav Pech Date: 30th Sep 2010

Field Summary
private SelectBase selectBase

 
Constructor Summary
Select(PGroup pGroup, DataflowReadChannel channels)

@param pGroup The group, the thread pool of which should be used for notification message handlers
Select(PGroup pGroup, java.util.List channels)

@param pGroup The group, the thread pool of which should be used for notification message handlers
 
Method Summary
SelectResult call()

Selects a value from a single randomly chosen input channel, which has a value available for read.
SelectResult call(java.util.List mask)

Selects a value from a single randomly chosen input channel, which has a value available for read.

void call(MessageStream messageStream)

Selects a value from a single randomly chosen input channel, which has a value available for read.

void call(MessageStream messageStream, java.util.List mask)

Selects a value from a single randomly chosen input channel, which has a value available for read.

SelectResult prioritySelect()

Selects a value from a single input channel, which has a value available for read.

SelectResult prioritySelect(java.util.List mask)

Selects a value from a single input channel, which has a value available for read.

void prioritySelect(MessageStream messageStream)

Selects a value from a single input channel, which has a value available for read.

void prioritySelect(MessageStream messageStream, java.util.List mask)

Selects a value from a single input channel, which has a value available for read.

SelectResult select()

Selects a value from a single randomly chosen input channel, which has a value available for read.
SelectResult select(java.util.List mask)

Selects a value from a single randomly chosen input channel, which has a value available for read.

void select(MessageStream messageStream)

Selects a value from a single randomly chosen input channel, which has a value available for read.

void select(MessageStream messageStream, java.util.List mask)

Selects a value from a single randomly chosen input channel, which has a value available for read.

private void select(MessageStream messageStream, int startIndex, java.util.List mask)

Invokes the internal select base with a SelectRequest instance ensuring a message is sent, once a value has been selected
private SelectResult select(int startIndex, java.util.List mask)

Invokes the internal select base with a SelectRequest instance ensuring the current thread can continue returning the correct value, once a value has been selected
 
Methods inherited from class java.lang.Object
java.lang.Object#wait(long), java.lang.Object#wait(), java.lang.Object#wait(long, int), java.lang.Object#equals(java.lang.Object), java.lang.Object#toString(), java.lang.Object#hashCode(), java.lang.Object#getClass(), java.lang.Object#notify(), java.lang.Object#notifyAll()
 

Field Detail

selectBase

private final SelectBase selectBase

 
Constructor Detail

Select

@SuppressWarnings({"OverloadedVarargsMethod"})
public Select(PGroup pGroup, DataflowReadChannel channels)
Parameters:
pGroup - The group, the thread pool of which should be used for notification message handlers
channels - The input channels to select from

Select

public Select(PGroup pGroup, java.util.List channels)
Parameters:
pGroup - The group, the thread pool of which should be used for notification message handlers
channels - The list of input channels to select from

 
Method Detail

call

public final SelectResult call()
Selects a value from a single randomly chosen input channel, which has a value available for read.
throws:
InterruptedException If the current thread gets interrupted
Returns:
The read value. It will be of SelectResult type, holding the actual value as well as the channel index.

call

public final SelectResult call(java.util.List mask)
Selects a value from a single randomly chosen input channel, which has a value available for read. Only the channels marked with 'true' in the supplied mask will be considered.
throws:
InterruptedException If the current thread gets interrupted
Parameters:
mask - A list of boolean values indicating, whether the input channel with the same position index should be included in the selection or not
Returns:
The read value. It will be of SelectResult type, holding the actual value as well as the channel index.

call

public final void call(MessageStream messageStream)
Selects a value from a single randomly chosen input channel, which has a value available for read. The read value is send to the supplied messageStream
throws:
InterruptedException If the current thread gets interrupted
Parameters:
messageStream - A message stream accepting the selected value. The message will be of SelectResult type, holding the actual value as well as the channel index.

call

public final void call(MessageStream messageStream, java.util.List mask)
Selects a value from a single randomly chosen input channel, which has a value available for read. The read value is send to the supplied messageStream
throws:
InterruptedException If the current thread gets interrupted
Parameters:
messageStream - A message stream accepting the selected value. The message will be of SelectResult type, holding the actual value as well as the channel index.
mask - A list of boolean values indicating, whether the input channel with the same position index should be included in the selection or not

prioritySelect

public SelectResult prioritySelect()
Selects a value from a single input channel, which has a value available for read. Channels with lower position index are preferred.
throws:
InterruptedException If the current thread gets interrupted
Returns:
The read value. It will be of SelectResult type, holding the actual value as well as the channel index.

prioritySelect

public SelectResult prioritySelect(java.util.List mask)
Selects a value from a single input channel, which has a value available for read. Channels with lower position index are preferred. Only the channels marked with 'true' in the supplied mask will be considered.
throws:
InterruptedException If the current thread gets interrupted
Parameters:
mask - A list of boolean values indicating, whether the input channel with the same position index should be included in the selection or not
Returns:
The read value. It will be of SelectResult type, holding the actual value as well as the channel index.

prioritySelect

public void prioritySelect(MessageStream messageStream)
Selects a value from a single input channel, which has a value available for read. Channels with lower position index are preferred. The read value is send to the supplied messageStream
throws:
InterruptedException If the current thread gets interrupted
Parameters:
messageStream - A message stream accepting the selected value. The message will be of SelectResult type, holding the actual value as well as the channel index.

prioritySelect

public void prioritySelect(MessageStream messageStream, java.util.List mask)
Selects a value from a single input channel, which has a value available for read. Channels with lower position index are preferred. The read value is send to the supplied messageStream
throws:
InterruptedException If the current thread gets interrupted
Parameters:
messageStream - A message stream accepting the selected value. The message will be of SelectResult type, holding the actual value as well as the channel index.
mask - A list of boolean values indicating, whether the input channel with the same position index should be included in the selection or not

select

public SelectResult select()
Selects a value from a single randomly chosen input channel, which has a value available for read.
throws:
InterruptedException If the current thread gets interrupted
Returns:
The read value. It will be of SelectResult type, holding the actual value as well as the channel index.

select

public SelectResult select(java.util.List mask)
Selects a value from a single randomly chosen input channel, which has a value available for read. Only the channels marked with 'true' in the supplied mask will be considered.
throws:
InterruptedException If the current thread gets interrupted
Parameters:
mask - A list of boolean values indicating, whether the input channel with the same position index should be included in the selection or not
Returns:
The read value. It will be of SelectResult type, holding the actual value as well as the channel index.

select

public void select(MessageStream messageStream)
Selects a value from a single randomly chosen input channel, which has a value available for read. The read value is send to the supplied messageStream
throws:
InterruptedException If the current thread gets interrupted
Parameters:
messageStream - A message stream accepting the selected value. The message will be of SelectResult type, holding the actual value as well as the channel index.

select

public void select(MessageStream messageStream, java.util.List mask)
Selects a value from a single randomly chosen input channel, which has a value available for read. The read value is send to the supplied messageStream
throws:
InterruptedException If the current thread gets interrupted
Parameters:
messageStream - A message stream accepting the selected value. The message will be of SelectResult type, holding the actual value as well as the channel index.
mask - A list of boolean values indicating, whether the input channel with the same position index should be included in the selection or not

select

private void select(MessageStream messageStream, int startIndex, java.util.List mask)
Invokes the internal select base with a SelectRequest instance ensuring a message is sent, once a value has been selected

select

private SelectResult select(int startIndex, java.util.List mask)
Invokes the internal select base with a SelectRequest instance ensuring the current thread can continue returning the correct value, once a value has been selected

 

Copyright © 2008–2010 Václav Pech. All Rights Reserved.