compact1, compact2, compact3
java.util.concurrent
Class AbstractExecutorService
- 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 ofExecutorServiceexecution methods. This class implements thesubmit,invokeAnyandinvokeAllmethods using aRunnableFuturereturned bynewTaskFor, which defaults to theFutureTaskclass provided in this package. For example, the implementation ofsubmit(Runnable)creates an associatedRunnableFuturethat is executed and returned. Subclasses may override thenewTaskFormethods to returnRunnableFutureimplementations other thanFutureTask.Extension example. Here is a sketch of a class that customizes
ThreadPoolExecutorto use aCustomTaskclass instead of the defaultFutureTask: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
All Methods Instance Methods Concrete 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> 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> 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.protected <T> RunnableFuture<T>newTaskFor(Callable<T> callable)Returns aRunnableFuturefor the given callable task.protected <T> RunnableFuture<T>newTaskFor(Runnable runnable, T value)Returns aRunnableFuturefor 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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Method Detail
newTaskFor
protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value)
Returns aRunnableFuturefor the given runnable and default value.- Type Parameters:
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T- the type of the given value - Parameters:
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runnable- the runnable task being wrapped -
value- the default value for the returned future - Returns:
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a
RunnableFuturewhich, when run, will run the underlying runnable and which, as aFuture, will yield the given value as its result and provide for cancellation of the underlying task - Since:
- 1.6
newTaskFor
protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable)
Returns aRunnableFuturefor the given callable task.- Type Parameters:
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T- the type of the callable's result - Parameters:
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callable- the callable task being wrapped - Returns:
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a
RunnableFuturewhich, when run, will call the underlying callable and which, as aFuture, will yield the callable's result as its result and provide for cancellation of the underlying task - Since:
- 1.6
submit
public Future<?> submit(Runnable task)
Description copied from interface:ExecutorServiceSubmits a Runnable task for execution and returns a Future representing that task. The Future'sgetmethod will returnnullupon successful completion.- Specified by:
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submitin interfaceExecutorService - Parameters:
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task- the task to submit - Returns:
- a Future representing pending completion of the task
- Throws:
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RejectedExecutionException- if the task cannot be scheduled for execution -
NullPointerException- if the task is null
submit
public <T> Future<T> submit(Runnable task, T result)
Description copied from interface:ExecutorServiceSubmits a Runnable task for execution and returns a Future representing that task. The Future'sgetmethod will return the given result upon successful completion.- Specified by:
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submitin interfaceExecutorService - Type Parameters:
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T- the type of the result - Parameters:
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task- the task to submit -
result- the result to return - Returns:
- a Future representing pending completion of the task
- Throws:
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RejectedExecutionException- if the task cannot be scheduled for execution -
NullPointerException- if the task is null
submit
public <T> Future<T> submit(Callable<T> task)
Description copied from interface:ExecutorServiceSubmits a value-returning task for execution and returns a Future representing the pending results of the task. The Future'sgetmethod 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
Executorsclass includes a set of methods that can convert some other common closure-like objects, for example,PrivilegedActiontoCallableform so they can be submitted.- Specified by:
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submitin interfaceExecutorService - Type Parameters:
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T- the type of the task's result - Parameters:
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task- the task to submit - Returns:
- a Future representing pending completion of the task
- Throws:
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RejectedExecutionException- if the task cannot be scheduled for execution -
NullPointerException- if the task is null
invokeAny
public <T> T invokeAny(Collection<? extends Callable<T>> tasks) throws InterruptedException, ExecutionException
Description copied from interface:ExecutorServiceExecutes 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:
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invokeAnyin interfaceExecutorService - Type Parameters:
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T- the type of the values returned from the tasks - Parameters:
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tasks- the collection of tasks - Returns:
- the result returned by one of the tasks
- Throws:
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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
Description copied from interface:ExecutorServiceExecutes 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:
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invokeAnyin interfaceExecutorService - Type Parameters:
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T- the type of the values returned from the tasks - Parameters:
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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:
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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<? extends Callable<T>> tasks) throws InterruptedException
Description copied from interface:ExecutorServiceExecutes the given tasks, returning a list of Futures holding their status and results when all complete.Future.isDone()istruefor 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:
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invokeAllin interfaceExecutorService - Type Parameters:
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T- the type of the values returned from the tasks - Parameters:
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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:
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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
Description copied from interface:ExecutorServiceExecutes 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()istruefor 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:
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invokeAllin interfaceExecutorService - Type Parameters:
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T- the type of the values returned from the tasks - Parameters:
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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:
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InterruptedException- if interrupted while waiting, in which case unfinished tasks are cancelled
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Submit a bug or feature
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