Class ForwardingExecutorService
- java.lang.Object
-
- com.google.common.collect.ForwardingObject
-
- com.google.common.util.concurrent.ForwardingExecutorService
-
- All Implemented Interfaces:
Executor
,ExecutorService
- Direct Known Subclasses:
ForwardingListeningExecutorService
@CanIgnoreReturnValue @GwtIncompatible public abstract class ForwardingExecutorService extends ForwardingObject implements ExecutorService
An executor service which forwards all its method calls to another executor service. Subclasses should override one or more methods to modify the behavior of the backing executor service as desired per the decorator pattern.- Since:
- 10.0
- Author:
- Kurt Alfred Kluever
-
-
Constructor Summary
Constructors Modifier Constructor Description protected
ForwardingExecutorService()
Constructor for use by subclasses.
-
Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description boolean
awaitTermination(long timeout, TimeUnit unit)
Blocks until all tasks have completed execution after a shutdown request, or the timeout occurs, or the current thread is interrupted, whichever happens first.protected abstract ExecutorService
delegate()
Returns the backing delegate instance that methods are forwarded to.void
execute(Runnable command)
Executes the given command at some time in the future.<T extends @Nullable Object>
List<Future<T>>invokeAll(Collection<? extends Callable<T>> tasks)
Executes the given tasks, returning a list of Futures holding their status and results when all complete.<T extends @Nullable Object>
List<Future<T>>invokeAll(Collection<? extends 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 extends @Nullable Object>
TinvokeAny(Collection<? extends 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 extends @Nullable Object>
TinvokeAny(Collection<? extends 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.boolean
isShutdown()
Returnstrue
if this executor has been shut down.boolean
isTerminated()
Returnstrue
if all tasks have completed following shut down.void
shutdown()
Initiates an orderly shutdown in which previously submitted tasks are executed, but no new tasks will be accepted.List<Runnable>
shutdownNow()
Attempts to stop all actively executing tasks, halts the processing of waiting tasks, and returns a list of the tasks that were awaiting execution.Future<?>
submit(Runnable task)
Submits a Runnable task for execution and returns a Future representing that task.<T extends @Nullable Object>
Future<T>submit(Runnable task, T result)
Submits a Runnable task for execution and returns a Future representing that task.<T extends @Nullable Object>
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 com.google.common.collect.ForwardingObject
toString
-
-
-
-
Constructor Detail
-
ForwardingExecutorService
protected ForwardingExecutorService()
Constructor for use by subclasses.
-
-
Method Detail
-
delegate
protected abstract ExecutorService delegate()
Description copied from class:ForwardingObject
Returns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such asForwardingSet.delegate()
. Concrete subclasses override this method to supply the instance being decorated.- Specified by:
delegate
in classForwardingObject
-
awaitTermination
public boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException
Description copied from interface:java.util.concurrent.ExecutorService
Blocks until all tasks have completed execution after a shutdown request, or the timeout occurs, or the current thread is interrupted, whichever happens first.- Specified by:
awaitTermination
in interfaceExecutorService
- Parameters:
timeout
- the maximum time to waitunit
- the time unit of the timeout argument- Returns:
true
if this executor terminated andfalse
if the timeout elapsed before termination- Throws:
InterruptedException
- if interrupted while waiting
-
invokeAll
public <T extends @Nullable Object> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) throws InterruptedException
Description copied from interface:java.util.concurrent.ExecutorService
Executes the given tasks, returning a list of Futures holding their status and results when all complete.Future.isDone()
istrue
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 interfaceExecutorService
- Type Parameters:
T
- the type of the values returned from the tasks- 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 extends @Nullable Object> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit) throws InterruptedException
Description copied from interface:java.util.concurrent.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()
istrue
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 interfaceExecutorService
- Type Parameters:
T
- the type of the values returned from the tasks- Parameters:
tasks
- the collection of taskstimeout
- the maximum time to waitunit
- 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 extends @Nullable Object> T invokeAny(Collection<? extends Callable<T>> tasks) throws InterruptedException, ExecutionException
Description copied from interface:java.util.concurrent.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 interfaceExecutorService
- Type Parameters:
T
- the type of the values returned from the tasks- Parameters:
tasks
- the collection of tasks- Returns:
- the result returned by one of the tasks
- Throws:
InterruptedException
- if interrupted while waitingExecutionException
- if no task successfully completes
-
invokeAny
public <T extends @Nullable Object> T invokeAny(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException
Description copied from interface:java.util.concurrent.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 interfaceExecutorService
- Type Parameters:
T
- the type of the values returned from the tasks- Parameters:
tasks
- the collection of taskstimeout
- the maximum time to waitunit
- the time unit of the timeout argument- Returns:
- the result returned by one of the tasks
- Throws:
InterruptedException
- if interrupted while waitingExecutionException
- if no task successfully completesTimeoutException
- if the given timeout elapses before any task successfully completes
-
isShutdown
public boolean isShutdown()
Description copied from interface:java.util.concurrent.ExecutorService
Returnstrue
if this executor has been shut down.- Specified by:
isShutdown
in interfaceExecutorService
- Returns:
true
if this executor has been shut down
-
isTerminated
public boolean isTerminated()
Description copied from interface:java.util.concurrent.ExecutorService
Returnstrue
if all tasks have completed following shut down. Note thatisTerminated
is nevertrue
unless eithershutdown
orshutdownNow
was called first.- Specified by:
isTerminated
in interfaceExecutorService
- Returns:
true
if all tasks have completed following shut down
-
shutdown
public void shutdown()
Description copied from interface:java.util.concurrent.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 interfaceExecutorService
-
shutdownNow
public List<Runnable> shutdownNow()
Description copied from interface:java.util.concurrent.ExecutorService
Attempts to stop all actively executing tasks, halts the processing of waiting tasks, and returns a list of the tasks that were awaiting execution.This method does not wait for actively executing tasks to terminate. Use
awaitTermination
to do that.There are no guarantees beyond best-effort attempts to stop processing actively executing tasks. For example, typical implementations will cancel via
Thread.interrupt()
, so any task that fails to respond to interrupts may never terminate.- Specified by:
shutdownNow
in interfaceExecutorService
- Returns:
- list of tasks that never commenced execution
-
execute
public void execute(Runnable command)
Description copied from interface:java.util.concurrent.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 theExecutor
implementation.
-
submit
public <T extends @Nullable Object> Future<T> submit(Callable<T> task)
Description copied from interface:java.util.concurrent.ExecutorService
Submits a value-returning task for execution and returns a Future representing the pending results of the task. The Future'sget
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();
Note: The
Executors
class includes a set of methods that can convert some other common closure-like objects, for example,PrivilegedAction
toCallable
form so they can be submitted.- Specified by:
submit
in interfaceExecutorService
- Type Parameters:
T
- the type of the task's result- Parameters:
task
- the task to submit- Returns:
- a Future representing pending completion of the task
-
submit
public Future<?> submit(Runnable task)
Description copied from interface:java.util.concurrent.ExecutorService
Submits a Runnable task for execution and returns a Future representing that task. The Future'sget
method will returnnull
upon successful completion.- Specified by:
submit
in interfaceExecutorService
- Parameters:
task
- the task to submit- Returns:
- a Future representing pending completion of the task
-
submit
public <T extends @Nullable Object> Future<T> submit(Runnable task, T result)
Description copied from interface:java.util.concurrent.ExecutorService
Submits a Runnable task for execution and returns a Future representing that task. The Future'sget
method will return the given result upon successful completion.- Specified by:
submit
in interfaceExecutorService
- Type Parameters:
T
- the type of the result- Parameters:
task
- the task to submitresult
- the result to return- Returns:
- a Future representing pending completion of the task
-
-