Type Parameters:

V - The result type returned by this Future's get method

All Known Subinterfaces:

Response<T>, RunnableFuture<V>, RunnableScheduledFuture<V>, ScheduledFuture<V>

All Known Implementing Classes:

ForkJoinTask, FutureTask, RecursiveAction, RecursiveTask, SwingWorker

public interface Future<V>

 interface ArchiveSearcher { String search(String target); }
 class App {
 ExecutorService executor = ...
 ArchiveSearcher searcher = ...
 void showSearch(final String target)
 throws InterruptedException {
 Future<String> future
 = executor.submit(new Callable<String>() {
 public String call() {
 return searcher.search(target);
 }});
 displayOtherThings(); // do other things while searching
 try {
 displayText(future.get()); // use future
 } catch (ExecutionException ex) { cleanup(); return; }
 }
 }

 FutureTask<String> future =
 new FutureTask<String>(new Callable<String>() {
 public String call() {
 return searcher.search(target);
 }});
 executor.execute(future);

Since:

1.5

See Also:

FutureTask, Executor

• Method Summary

  Methods

  Modifier and Type	Method and Description
  boolean	cancel (boolean mayInterruptIfRunning) Attempts to cancel execution of this task.
  V	get () Waits if necessary for the computation to complete, and then retrieves its result.
  V	get (long timeout, TimeUnit unit) Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available.
  boolean	isCancelled () Returns true if this task was cancelled before it completed normally.
  boolean	isDone () Returns true if this task completed.

• Method Detail

  • cancel

    boolean cancel(boolean mayInterruptIfRunning)

    Attempts to cancel execution of this task. This attempt will fail if the task has already completed, has already been cancelled, or could not be cancelled for some other reason. If successful, and this task has not started when cancel is called, this task should never run. If the task has already started, then the mayInterruptIfRunning parameter determines whether the thread executing this task should be interrupted in an attempt to stop the task.

    After this method returns, subsequent calls to isDone() will always return true. Subsequent calls to isCancelled() will always return true if this method returned true.

    Parameters:

    mayInterruptIfRunning - true if the thread executing this task should be interrupted; otherwise, in-progress tasks are allowed to complete

    Returns:

    false if the task could not be cancelled, typically because it has already completed normally; true otherwise

  • isCancelled

    boolean isCancelled()

    Returns true if this task was cancelled before it completed normally.

    Returns:

    true if this task was cancelled before it completed

  • isDone

    boolean isDone()

    Returns true if this task completed. Completion may be due to normal termination, an exception, or cancellation -- in all of these cases, this method will return true.

    Returns:

    true if this task completed

  • get

    V get()
     throws InterruptedException,
     ExecutionException 

    Waits if necessary for the computation to complete, and then retrieves its result.

    Returns:

    the computed result

    Throws:

    CancellationException - if the computation was cancelled

    ExecutionException - if the computation threw an exception

    InterruptedException - if the current thread was interrupted while waiting

  • get

    V get(long timeout,
     TimeUnit unit)
     throws InterruptedException,
     ExecutionException,
     TimeoutException 

    Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available.

    Parameters:

    timeout - the maximum time to wait

    unit - the time unit of the timeout argument

    Returns:

    the computed result

    Throws:

    CancellationException - if the computation was cancelled

    ExecutionException - if the computation threw an exception

    InterruptedException - if the current thread was interrupted while waiting

    TimeoutException - if the wait timed out