org.springframework.batch.poller

Interface Poller<T>

All Known Implementing Classes:

DirectPoller

public interface Poller<T>

Interface for polling a Callable instance provided by the user. Use when you need to put something in the background (e.g. a remote invocation) and wait for the result, e.g.

 Poller<Result> poller = ...
 
 final long id = remoteService.execute(); // do something remotely
 
 Future<Result> future = poller.poll(new Callable<Result> {
     public Object call() {
           // Look for the result (null if not ready)
           return remoteService.get(id);
     }
 });
 
 Result result = future.get(1000L, TimeUnit.MILLISECONDS);
 

Author:

Dave Syer, Mahmoud Ben Hassine

Method Summary

Modifier and Type	Method and Description
java.util.concurrent.Future<T>	poll(java.util.concurrent.Callable<T> callable) Use the callable provided to poll for a non-null result.

Method Detail

poll

java.util.concurrent.Future<T> poll(java.util.concurrent.Callable<T> callable)
                             throws java.lang.Exception

Use the callable provided to poll for a non-null result. The callable might be executed multiple times searching for a result, but once either a result or an exception has been observed the polling stops.

Parameters:

callable - a Callable to use to retrieve a result

Returns:

a future which itself can be used to get the result

Throws:

java.lang.Exception - allows for checked exceptions