Promise

java.lang.Object
- org.jgroups.util.Promise<T>

```
public class Promise<T>
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.

Version:

$Id: Promise.java,v 1.12.2.1 2007/11/20 08:37:24 belaban Exp $

Author:

Bela Ban

Constructor Summary

Constructors
Constructor Description

Promise()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`java.util.concurrent.locks.Condition`	`getCond()`
`java.util.concurrent.locks.Lock`	`getLock()`
`T`	`getResult()`
`T`	`getResult(long timeout)`	Returns the result, but never throws a TimeoutException; returns null instead.
`T`	`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(T 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
  - getLock
```
public java.util.concurrent.locks.Lock getLock()
```
  - getCond
```
public java.util.concurrent.locks.Condition getCond()
```
  - getResultWithTimeout
```
public T 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)
  - getResult
```
public T getResult()
```
  - getResult
```
public T 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(T 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