public abstract class AbstractExecutorService extends Object implements ExecutorService
ExecutorService
execution methods. This class implements the submit,
invokeAny and invokeAll methods using a
RunnableFuture returned by newTaskFor, which defaults
to the FutureTask 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.
}| Constructor and Description |
|---|
AbstractExecutorService() |
| 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.
|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitawaitTermination, isShutdown, isTerminated, shutdown, shutdownNowprotected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value)
RunnableFuture for the given runnable and default
value.T - the type of the given valuerunnable - the runnable task being wrappedvalue - the default value for the returned futureRunnableFuture 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 taskprotected <T> RunnableFuture<T> newTaskFor(Callable<T> callable)
RunnableFuture for the given callable task.T - the type of the callable's resultcallable - the callable task being wrappedRunnableFuture 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 taskpublic Future<?> submit(Runnable task)
ExecutorServiceget method will
return null upon successful completion.submit in interface ExecutorServicetask - the task to submitRejectedExecutionException - if the task cannot be
scheduled for executionNullPointerException - if the task is nullpublic <T> Future<T> submit(Runnable task, T result)
ExecutorServiceget method will
return the given result upon successful completion.submit in interface ExecutorServiceT - the type of the resulttask - the task to submitresult - the result to returnRejectedExecutionException - if the task cannot be
scheduled for executionNullPointerException - if the task is nullpublic <T> Future<T> submit(Callable<T> task)
ExecutorServiceget 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 to
Callable form so they can be submitted.
submit in interface ExecutorServiceT - the type of the task's resulttask - the task to submitRejectedExecutionException - if the task cannot be
scheduled for executionNullPointerException - if the task is nullpublic <T> T invokeAny(Collection<? extends Callable<T>> tasks) throws InterruptedException, ExecutionException
ExecutorServiceinvokeAny in interface ExecutorServiceT - the type of the values returned from the taskstasks - the collection of tasksInterruptedException - if interrupted while waitingExecutionException - if no task successfully completespublic <T> T invokeAny(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException
ExecutorServiceinvokeAny in interface ExecutorServiceT - the type of the values returned from the taskstasks - the collection of taskstimeout - the maximum time to waitunit - the time unit of the timeout argumentInterruptedException - if interrupted while waitingExecutionException - if no task successfully completesTimeoutException - if the given timeout elapses before
any task successfully completespublic <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) throws InterruptedException
ExecutorServiceFuture.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.invokeAll in interface ExecutorServiceT - the type of the values returned from the taskstasks - the collection of tasksInterruptedException - if interrupted while waiting, in
which case unfinished tasks are cancelledpublic <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit) throws InterruptedException
ExecutorServiceFuture.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.invokeAll in interface ExecutorServiceT - the type of the values returned from the taskstasks - the collection of taskstimeout - the maximum time to waitunit - the time unit of the timeout argumentInterruptedException - if interrupted while waiting, in
which case unfinished tasks are cancelled Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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