org.jgroups.util

Class Promise

java.lang.Object

org.jgroups.util.Promise

public class Promise
extends java.lang.Object

Allows a thread to submit an asynchronous request and to wait for the result. The caller may choose to check for the result at a later time, or immediately and it may block or not. Both the caller and responder have to know the promise.

Author:

Bela Ban

Constructor Summary

Constructors

Constructor and Description
Promise()

Method Summary

Methods

Modifier and Type	Method and Description
java.lang.Object	getResult()
java.lang.Object	getResult(long timeout) Returns the result, but never throws a TimeoutException; returns null instead.
java.lang.Object	getResultWithTimeout(long timeout) Blocks until a result is available, or timeout milliseconds have elapsed
boolean	hasResult() Checks whether result is available.
void	reset() Causes all waiting threads to return
void	setResult(java.lang.Object obj) Sets the result and notifies any threads waiting for it
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

Promise

public Promise()

Method Detail

getResultWithTimeout

public java.lang.Object getResultWithTimeout(long timeout)
                                      throws TimeoutException

Blocks until a result is available, or timeout milliseconds have elapsed

Parameters:

timeout -

Returns:

An object

Throws:

TimeoutException. - If a timeout occurred (implies that timeout > 0)

TimeoutException

getResult

public java.lang.Object getResult()

getResult

public java.lang.Object getResult(long timeout)

Returns the result, but never throws a TimeoutException; returns null instead.

Parameters:

timeout -

Returns:

Object

hasResult

public boolean hasResult()

Checks whether result is available. Does not block.

setResult

public void setResult(java.lang.Object obj)

Sets the result and notifies any threads waiting for it

reset

public void reset()

Causes all waiting threads to return

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object