java.util.concurrent
Class AbstractExecutorService

java.lang.Object
  java.util.concurrent.AbstractExecutorService

All Implemented Interfaces:

Executor, ExecutorService

Direct Known Subclasses:

ThreadPoolExecutor

public abstract class AbstractExecutorService
extends Object
implements ExecutorService

Provides default implementation of ExecutorService execution methods. This class implements the submit, invokeAny and invokeAll methods using the default FutureTask class provided in this package. For example, the implementation of submit(Runnable) creates an associated FutureTask that is executed and returned. Subclasses overriding these methods to use different Future implementations should do so consistently for each of these methods.

Since:

1.5

Constructor Summary

AbstractExecutorService()

Method Summary

<T> List<Future<T>>	invokeAll(Collection<Callable<T>> tasks) Executes the given tasks, returning a list of Futures holding their status and results when all complete.
<T> List<Future<T>>	invokeAll(Collection<Callable<T>> tasks, long timeout, TimeUnit unit) Executes the given tasks, returning a list of Futures holding their status and results when all complete or the timeout expires, whichever happens first.
<T> T	invokeAny(Collection<Callable<T>> tasks) Executes the given tasks, returning the result of one that has completed successfully (i.e., without throwing an exception), if any do.
<T> T	invokeAny(Collection<Callable<T>> tasks, long timeout, TimeUnit unit) Executes the given tasks, returning the result of one that has completed successfully (i.e., without throwing an exception), if any do before the given timeout elapses.
<T> Future<T>	submit(Callable<T> task) Submits a value-returning task for execution and returns a Future representing the pending results of the task.
Future<?>	submit(Runnable task) Submits a Runnable task for execution and returns a Future representing that task.
<T> Future<T>	submit(Runnable task, T result) Submits a Runnable task for execution and returns a Future representing that task that will upon completion return the given result

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.concurrent.ExecutorService

awaitTermination, isShutdown, isTerminated, shutdown, shutdownNow

Methods inherited from interface java.util.concurrent.Executor

execute

Constructor Detail

AbstractExecutorService

public AbstractExecutorService()

Method Detail

submit

public Future<?> submit(Runnable task)

Description copied from interface: ExecutorService

Submits a Runnable task for execution and returns a Future representing that task.

Specified by:

submit in interface ExecutorService

Parameters:

task - the task to submit

Returns:

a Future representing pending completion of the task, and whose get() method will return null upon completion.

submit

public <T> Future<T> submit(Runnable task,
                            T result)

Description copied from interface: ExecutorService

Submits a Runnable task for execution and returns a Future representing that task that will upon completion return the given result

Specified by:

submit in interface ExecutorService

Parameters:

task - the task to submit

result - the result to return

Returns:

a Future representing pending completion of the task, and whose get() method will return the given result upon completion.

submit

public <T> Future<T> submit(Callable<T> task)

Description copied from interface: ExecutorService

Submits a value-returning task for execution and returns a Future representing the pending results of the task.

If you would like to immediately block waiting for a task, you can use constructions of the form result = exec.submit(aCallable).get();

Note: The Executors class includes a set of methods that can convert some other common closure-like objects, for example, PrivilegedAction to Callable form so they can be submitted.

Specified by:

submit in interface ExecutorService

Parameters:

task - the task to submit

Returns:

a Future representing pending completion of the task

invokeAny

public <T> T invokeAny(Collection<Callable<T>> tasks)
            throws InterruptedException,
                   ExecutionException

Description copied from interface: ExecutorService

Executes the given tasks, returning the result of one that has completed successfully (i.e., without throwing an exception), if any do. Upon normal or exceptional return, tasks that have not completed are cancelled. The results of this method are undefined if the given collection is modified while this operation is in progress.

Specified by:

invokeAny in interface ExecutorService

Parameters:

tasks - the collection of tasks

Returns:

The result returned by one of the tasks.

Throws:

InterruptedException - if interrupted while waiting

ExecutionException - if no task successfully completes

invokeAny

public <T> T invokeAny(Collection<Callable<T>> tasks,
                       long timeout,
                       TimeUnit unit)
            throws InterruptedException,
                   ExecutionException,
                   TimeoutException

Description copied from interface: ExecutorService

Executes the given tasks, returning the result of one that has completed successfully (i.e., without throwing an exception), if any do before the given timeout elapses. Upon normal or exceptional return, tasks that have not completed are cancelled. The results of this method are undefined if the given collection is modified while this operation is in progress.

Specified by:

invokeAny in interface ExecutorService

Parameters:

tasks - the collection of tasks

timeout - the maximum time to wait

unit - the time unit of the timeout argument

Returns:

The result returned by one of the tasks.

Throws:

InterruptedException - if interrupted while waiting

ExecutionException - if no task successfully completes

TimeoutException - if the given timeout elapses before any task successfully completes

invokeAll

public <T> List<Future<T>> invokeAll(Collection<Callable<T>> tasks)
                          throws InterruptedException

Description copied from interface: ExecutorService

Executes the given tasks, returning a list of Futures holding their status and results when all complete. Future.isDone() is true for each element of the returned list. Note that a completed task could have terminated either normally or by throwing an exception. The results of this method are undefined if the given collection is modified while this operation is in progress.

Specified by:

invokeAll in interface ExecutorService

Parameters:

tasks - the collection of tasks

Returns:

A list of Futures representing the tasks, in the same sequential order as produced by the iterator for the given task list, each of which has completed.

Throws:

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

invokeAll

public <T> List<Future<T>> invokeAll(Collection<Callable<T>> tasks,
                                     long timeout,
                                     TimeUnit unit)
                          throws InterruptedException

Description copied from interface: ExecutorService

Executes the given tasks, returning a list of Futures holding their status and results when all complete or the timeout expires, whichever happens first. Future.isDone() is true for each element of the returned list. Upon return, tasks that have not completed are cancelled. Note that a completed task could have terminated either normally or by throwing an exception. The results of this method are undefined if the given collection is modified while this operation is in progress.

Specified by:

invokeAll in interface ExecutorService

Parameters:

tasks - the collection of tasks

timeout - the maximum time to wait

unit - the time unit of the timeout argument

Returns:

A list of Futures representing the tasks, in the same sequential order as produced by the iterator for the given task list. If the operation did not time out, each task will have completed. If it did time out, some of these tasks will not have completed.

Throws:

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