com.bigdata.util.concurrent

Class ExecutionHelper<T>

java.lang.Object

com.bigdata.util.concurrent.ExecutionHelper<T>

Type Parameters:

T - The generic type of the values returned by the Callable tasks.

public class ExecutionHelper<T>
extends Object

Helper class for managing the execution of a set of Callable tasks on an ExecutorService.

Version:

$Id$

Author:

Bryan Thompson

Constructor Summary

Constructors

Constructor and Description
ExecutionHelper(ExecutorService service) Tasks will execute without timeout.
ExecutionHelper(ExecutorService service, long timeout, TimeUnit unit) Tasks will execute with the specified timeout.

Method Summary

Methods

Modifier and Type	Method and Description
void	submitTasks(List<Callable<T>> tasks) Submit subquery tasks, wait until they are done, and verify that all tasks were executed without error.

Methods inherited from class java.lang.Object

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

Constructor Detail

ExecutionHelper

public ExecutionHelper(ExecutorService service)

Tasks will execute without timeout.

Parameters:

service - The service on which the tasks will be executed.

ExecutionHelper

public ExecutionHelper(ExecutorService service,
               long timeout,
               TimeUnit unit)

Tasks will execute with the specified timeout.

Parameters:

service - The service on which the tasks will be executed.

timeout - The timeout for the tasks when submitted.

unit - The unit in which that timeout is expressed.

Method Detail

submitTasks

public void submitTasks(List<Callable<T>> tasks)
                 throws InterruptedException,
                        ExecutionExceptions

Submit subquery tasks, wait until they are done, and verify that all tasks were executed without error. A variety of steps are taken to normalize handling interrupts, canceled execution due to timeout, and rejected execution when the ExecutorService has been shutdown.

Parameters:

tasks - The tasks.

Throws:

InterruptedException - Tasks that are interrupted and tasks that are canceled due to timeout result in a logged warning and a thrown InterruptedException. Likewise, if a RejectedExecutionException is thrown and the service is shutdown, then that exception is converted into an InterruptedException.

RejectedExecutionException - If a RejectedExecutionException is thrown and the executor service has not been shutdown.

ExecutionExceptions - If one or more tasks fails. The causes thrown by the various tasks are available as an aid to debugging.