org.deegree.commons.concurrent
Class Executor

java.lang.Object
  org.deegree.commons.concurrent.Executor

public class Executor
extends Object

The Executor is deegree's central place to:

• Perform a task asynchronously (in an independent thread) optionally with a maximum execution time.
• Perform a task synchronously with a maximum execution time.
• Perform several task synchronously (but in parallel threads) with a maximum execution time.

The Executor class is realized as a singleton and uses a cached thread pool internally to minimize overhead for acquiring the necessary Thread instances and to manage the number of concurrent threads.

Version:

$Revision: 9339 $, $Date: 2007-12-27 12:31:52 +0000 (Do, 27 Dez 2007) $

Author:

Andreas Poth, Andreas Schmitz, Rutger Bezema, Markus Schneider, last edited by: $Author: apoth $

See Also:

ExecutorService, ExecutionFinishedListener

Method Summary

static Executor	getInstance() Returns the only instance of this class (singleton pattern).
<T> void	performAsynchronously(Callable<T> task, ExecutionFinishedListener<T> finishedListener) Performs a task asynchronously (in an independent thread) without any time limit.
<T> void	performAsynchronously(Callable<T> task, ExecutionFinishedListener<T> finishedListener, long timeout) Performs a task asynchronously (in an independent thread) with a given time limit.
<T> T	performSynchronously(Callable<T> task, long timeout) Performs a task synchronously with a given timeout.
<T> List<ExecutionFinishedEvent<T>>	performSynchronously(List<Callable<T>> tasks) Performs several tasks synchronously in parallel threads.
<T> List<ExecutionFinishedEvent<T>>	performSynchronously(List<Callable<T>> tasks, long timeout) Performs several tasks synchronously with a given timeout in parallel threads.

Methods inherited from class java.lang.Object

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

Method Detail

getInstance

public static Executor getInstance()

Returns the only instance of this class (singleton pattern).

Returns:

the only instance of this class

performAsynchronously

public <T> void performAsynchronously(Callable<T> task,
                                      ExecutionFinishedListener<T> finishedListener)

Performs a task asynchronously (in an independent thread) without any time limit.

Type Parameters:

T - type of return value

Parameters:

task - task to be performed (specified in the Callable.call() method)

finishedListener - notified when the method call finishes (succesfully or abnormally), may be null

performAsynchronously

public <T> void performAsynchronously(Callable<T> task,
                                      ExecutionFinishedListener<T> finishedListener,
                                      long timeout)

Performs a task asynchronously (in an independent thread) with a given time limit.

Type Parameters:

T - type of return value

Parameters:

task - task to be performed (specified in the Callable.call()} method)

finishedListener - notified when the method call finishes (succesfully or abnormally), may be null

timeout - maximum time allowed for execution in milliseconds

performSynchronously

public <T> T performSynchronously(Callable<T> task,
                                  long timeout)
                       throws CancellationException,
                              InterruptedException,
                              Throwable

Performs a task synchronously with a given timeout.

Type Parameters:

T - type of return value

Parameters:

task - tasks to be performed (specified in the Callable.call() method)

timeout - maximum time allowed for execution in milliseconds

Returns:

result value of the called method

Throws:

CancellationException - if the execution time exceeds the specified timeout / thread has been cancelled

InterruptedException - if interrupted while waiting, in which case unfinished tasks are cancelled

Throwable - if the tasks throws an exception itself

performSynchronously

public <T> List<ExecutionFinishedEvent<T>> performSynchronously(List<Callable<T>> tasks)
                                                     throws InterruptedException

Performs several tasks synchronously in parallel threads.

This method does not return before all tasks are finished (successfully or abnormally). For each given Callable, an independent thread is used. For each task, an ExecutionFinishedEvent is generated and returned.

Type Parameters:

T - the result type of the callables

Parameters:

tasks - tasks to be performed (specified in the Callable.call() methods)

Returns:

ExecutionFinishedEvents for all tasks

Throws:

InterruptedException - if the current thread was interrupted while waiting

performSynchronously

public <T> List<ExecutionFinishedEvent<T>> performSynchronously(List<Callable<T>> tasks,
                                                                long timeout)
                                                     throws InterruptedException

Performs several tasks synchronously with a given timeout in parallel threads.

This method does not return before all tasks are finished (successfully or abnormally). For each given Callable, an independent thread is used. For each task, an ExecutionFinishedEvent is generated and returned.

Type Parameters:

T - the result type of the tasks

Parameters:

tasks - tasks to be performed (specified in the Callable.call() methods)

timeout - maximum time allowed for execution (in milliseconds)

Returns:

ExecutionFinishedEvents for all tasks

Throws:

InterruptedException - if the current thread was interrupted while waiting