Package ej.util.concurrent

Class SingleThreadExecutor

java.lang.Object

ej.util.concurrent.SingleThreadExecutor

All Implemented Interfaces:

Runnable, Executor, ExecutorService

public class SingleThreadExecutor
extends Object
implements Runnable, ExecutorService

An executor that uses a single worker thread operating off an unbounded queue.

Constructor Summary

Constructors

Constructor	Description
SingleThreadExecutor()	Creates a single thread executor.

Method Summary

Modifier and Type	Method	Description
boolean	awaitTermination(long timeout, TimeUnit unit)	This method is unsupported by this implementation.
void	execute(Runnable r)	Executes the given command at some time in the future.
<T> List<Future<T>>	invokeAll(Collection<? extends Callable<T>> tasks)	This method is unsupported by this implementation.
<T> List<Future<T>>	invokeAll(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)	This method is unsupported by this implementation.
<T> T	invokeAny(Collection<? extends Callable<T>> tasks)	This method is unsupported by this implementation.
<T> T	invokeAny(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)	This method is unsupported by this implementation.
boolean	isShutdown()	Returns true if this executor has been shut down.
boolean	isTerminated()	Returns true if all tasks have completed following shut down.
void	run()	When an object implementing interface Runnable is used to create a thread, starting the thread causes the object's run method to be called in that separately executing thread.
void	shutdown()	Initiates an orderly shutdown in which previously submitted tasks are executed, but no new tasks will be accepted.
List<Runnable>	shutdownNow()	This method is unsupported by this implementation.
Future<?>	submit(Runnable task)	This method is unsupported by this implementation.
<T> Future<T>	submit(Runnable task, T result)	This method is unsupported by this implementation.
<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.

Methods inherited from class java.lang.Object

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

Constructor Detail

SingleThreadExecutor

public SingleThreadExecutor()

Creates a single thread executor.

A new thread is created and started immediately.

Method Detail

run

public void run()

Description copied from interface: Runnable

When an object implementing interface Runnable is used to create a thread, starting the thread causes the object's run method to be called in that separately executing thread.

The general contract of the method run is that it may take any action whatsoever.

Specified by:

run in interface Runnable

See Also:

Thread.run()

execute

public void execute(Runnable r)

Description copied from interface: Executor

Executes the given command at some time in the future. The command may execute in a new thread, in a pooled thread, or in the calling thread, at the discretion of the Executor implementation.

Specified by:

execute in interface Executor

Parameters:

r - the runnable task

shutdown

public void shutdown()

Description copied from interface: ExecutorService

Initiates an orderly shutdown in which previously submitted tasks are executed, but no new tasks will be accepted. Invocation has no additional effect if already shut down.

This method does not wait for previously submitted tasks to complete execution. Use awaitTermination to do that.

Specified by:

shutdown in interface ExecutorService

shutdownNow

public List<Runnable> shutdownNow()

This method is unsupported by this implementation.

Calling this method will throw an UnsupportedOperationException.

Specified by:

shutdownNow in interface ExecutorService

Returns:

list of tasks that never commenced execution

isShutdown

public boolean isShutdown()

Description copied from interface: ExecutorService

Returns true if this executor has been shut down.

Specified by:

isShutdown in interface ExecutorService

Returns:

true if this executor has been shut down

isTerminated

public boolean isTerminated()

Description copied from interface: ExecutorService

Returns true if all tasks have completed following shut down. Note that isTerminated is never true unless either shutdown or shutdownNow was called first.

Specified by:

isTerminated in interface ExecutorService

Returns:

true if all tasks have completed following shut down

awaitTermination

public boolean awaitTermination(long timeout,
                                TimeUnit unit)
                         throws InterruptedException

This method is unsupported by this implementation.

Calling this method will throw an UnsupportedOperationException.

Specified by:

awaitTermination in interface ExecutorService

Parameters:

timeout - the maximum time to wait

unit - the time unit of the timeout argument

Returns:

true if this executor terminated and false if the timeout elapsed before termination

Throws:

InterruptedException - if interrupted while waiting

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. The Future's get method will return the task's result upon successful completion.

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

Specified by:

submit in interface ExecutorService

Parameters:

task - the task to submit

Returns:

a Future representing pending completion of the task

submit

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

This method is unsupported by this implementation.

Calling this method will throw an UnsupportedOperationException.

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

submit

public Future<?> submit(Runnable task)

This method is unsupported by this implementation.

Calling this method will throw an UnsupportedOperationException.

Specified by:

submit in interface ExecutorService

Parameters:

task - the task to submit

Returns:

a Future representing pending completion of the task

invokeAll

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

This method is unsupported by this implementation.

Calling this method will throw an UnsupportedOperationException.

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<? extends Callable<T>> tasks,
                                     long timeout,
                                     TimeUnit unit)
                              throws InterruptedException

This method is unsupported by this implementation.

Calling this method will throw an UnsupportedOperationException.

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

invokeAny

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

This method is unsupported by this implementation.

Calling this method will throw an UnsupportedOperationException.

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<? extends Callable<T>> tasks,
                       long timeout,
                       TimeUnit unit)
                throws InterruptedException,
                       ExecutionException,
                       TimeoutException

This method is unsupported by this implementation.

Calling this method will throw an UnsupportedOperationException.

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