- java.lang.Object
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- java.util.concurrent.AbstractExecutorService
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- All Implemented Interfaces:
- Executor, ExecutorService
- Direct Known Subclasses:
- ForkJoinPool, ThreadPoolExecutor
public abstract class AbstractExecutorService extends Object implements ExecutorService
Provides default implementations ofExecutorService
execution methods. This class implements the submit, invokeAny and invokeAll methods using aRunnableFuture
returned by newTaskFor, which defaults to theFutureTask
class provided in this package. For example, the implementation of submit(Runnable) creates an associated RunnableFuture that is executed and returned. Subclasses may override the newTaskFor methods to return RunnableFuture implementations other than FutureTask.Extension example. Here is a sketch of a class that customizes
ThreadPoolExecutor
to use a CustomTask class instead of the default FutureTask:public class CustomThreadPoolExecutor extends ThreadPoolExecutor { static class CustomTask<V> implements RunnableFuture<V> {...} protected <V> RunnableFuture<V> newTaskFor(Callable<V> c) { return new CustomTask<V>(c); } protected <V> RunnableFuture<V> newTaskFor(Runnable r, V v) { return new CustomTask<V>(r, v); } // ... add constructors, etc. }
- Since:
- 1.5
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Constructor Summary
Constructors Constructor and Description AbstractExecutorService()
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Method Summary
Methods Modifier and Type Method and Description <T> 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> 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> T
invokeAny(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> T
invokeAny(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.protected <T> RunnableFuture<T>
newTaskFor(Callable<T> callable)
Returns a RunnableFuture for the given callable task.protected <T> RunnableFuture<T>
newTaskFor(Runnable runnable, T value)
Returns a RunnableFuture for the given runnable and default value.<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.-
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface java.util.concurrent.ExecutorService
awaitTermination, isShutdown, isTerminated, shutdown, shutdownNow
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Methods inherited from interface java.util.concurrent.Executor
execute
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Method Detail
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newTaskFor
protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value)
Returns a RunnableFuture for the given runnable and default value.- Parameters:
runnable
- the runnable task being wrappedvalue
- the default value for the returned future- Returns:
- a RunnableFuture which when run will run the underlying runnable and which, as a Future, will yield the given value as its result and provide for cancellation of the underlying task.
- Since:
- 1.6
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newTaskFor
protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable)
Returns a RunnableFuture for the given callable task.- Parameters:
callable
- the callable task being wrapped- Returns:
- a RunnableFuture which when run will call the underlying callable and which, as a Future, will yield the callable's result as its result and provide for cancellation of the underlying task.
- Since:
- 1.6
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submit
public Future<?> submit(Runnable task)
Description copied from interface:ExecutorService
Submits a Runnable task for execution and returns a Future representing that task. The Future's get method will return null upon successful completion.- Specified by:
submit
in interfaceExecutorService
- Parameters:
task
- the task to submit- Returns:
- a Future representing pending completion of the task
- Throws:
RejectedExecutionException
- if the task cannot be scheduled for executionNullPointerException
- if the task is null
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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. The Future's get method will return the given result upon successful completion.- Specified by:
submit
in interfaceExecutorService
- Parameters:
task
- the task to submitresult
- the result to return- Returns:
- a Future representing pending completion of the task
- Throws:
RejectedExecutionException
- if the task cannot be scheduled for executionNullPointerException
- if the task is null
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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();
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
- Parameters:
task
- the task to submit- Returns:
- a Future representing pending completion of the task
- Throws:
RejectedExecutionException
- if the task cannot be scheduled for executionNullPointerException
- if the task is null
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invokeAny
public <T> T invokeAny(Collection<? extends 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 interfaceExecutorService
- 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
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invokeAny
public <T> T invokeAny(Collection<? extends 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 interfaceExecutorService
- 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
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invokeAll
public <T> List<Future<T>> invokeAll(Collection<? extends 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 interfaceExecutorService
- 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.
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invokeAll
public <T> List<Future<T>> invokeAll(Collection<? extends 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 interfaceExecutorService
- 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
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Document created the 11/06/2005, last modified the 04/03/2020
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