groovyx.gpars.dataflow
[Java] Interface Promise

public interface Promise

A unifying future-like interface to dataflow variables, asynchronous functions and active objects.

Authors:

Vaclav Pech

get

@SuppressWarnings({"ProhibitedExceptionDeclared"})
public T get()

Retrieves the value of the variable, blocking until a value is available

throws:

Throwable If the stored value is an exception instance it gets re-thrown

Returns:

The value stored in the variable

get

@SuppressWarnings({"ProhibitedExceptionDeclared"})
public T get(long timeout, java.util.concurrent.TimeUnit units)

Retrieves the value of the variable, blocking up to given timeout, if the value has not been assigned yet.

throws:

Throwable If the stored value is an exception instance it gets re-thrown

Parameters:

timeout - The timeout value

units - Units for the timeout

Returns:

The value stored in the variable

getVal

public T getVal()

Reads the current value of the channel. Blocks, if the value has not been assigned yet.

throws:

InterruptedException If the current thread gets interrupted while waiting for the channel to be bound

Returns:

The actual value

getVal

public T getVal(long timeout, java.util.concurrent.TimeUnit units)

Reads the current value of the channel. Blocks up to given timeout, if the value has not been assigned yet.

throws:

InterruptedException If the current thread gets interrupted while waiting for the channel to be bound

Parameters:

timeout - The timeout value

units - Units for the timeout

Returns:

The actual value

getValAsync

public void getValAsync(MessageStream callback)

Asynchronously retrieves the value from the channel. Sends the actual value of the channel as a message back the the supplied actor once the value has been bound. The actor can perform other activities or release a thread back to the pool by calling react() waiting for the message with the value of the Dataflow channel.

Parameters:

callback - An actor to send the bound value to.

getValAsync

public void getValAsync(java.lang.Object attachment, MessageStream callback)

Asynchronously retrieves the value from the channel. Sends a message back the the supplied MessageStream with a map holding the supplied attachment under the 'attachment' key and the actual value of the channel under the 'result' key once the value has been bound. Attachment is an arbitrary value helping the actor.operator match its request with the reply. The actor/operator can perform other activities or release a thread back to the pool by calling react() waiting for the message with the value of the Dataflow channel.

Parameters:

attachment - arbitrary non-null attachment if reader needs better identification of result

callback - An actor to send the bound value plus the supplied index to.

isBound

public boolean isBound()

Check if value has been set already for this expression

Returns:

true if bound already

rightShift

public void rightShift(groovy.lang.Closure closure)

Schedule closure to be executed by pooled actor after data became available It is important to notice that even if data already available the execution of closure will not happen immediately but will be scheduled

Parameters:

closure - closure to execute when data available

whenBound

public void whenBound(groovy.lang.Closure closure)

Schedule closure to be executed by pooled actor after data becomes available It is important to notice that even if data already available the execution of closure will not happen immediately but will be scheduled.

Parameters:

closure - closure to execute when data available

whenBound

public void whenBound(Pool pool, groovy.lang.Closure closure)

Schedule closure to be executed by pooled actor after data becomes available It is important to notice that even if data already available the execution of closure will not happen immediately but will be scheduled.

Parameters:

pool - The thread pool to use for task scheduling for asynchronous message delivery

closure - closure to execute when data available

whenBound

public void whenBound(PGroup group, groovy.lang.Closure closure)

Schedule closure to be executed by pooled actor after data becomes available It is important to notice that even if data already available the execution of closure will not happen immediately but will be scheduled.

Parameters:

group - The PGroup to use for task scheduling for asynchronous message delivery

closure - closure to execute when data available

whenBound

public void whenBound(MessageStream stream)

Send the bound data to provided stream when it becomes available

Parameters:

stream - stream where to send result

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