java.util.concurrent
Interface Cancellable
- All Known Subinterfaces:
- Future, ScheduledCancellable, ScheduledFuture
- All Known Implementing Classes:
- CancellableTask, CancellableTask.InnerCancellableFuture, FutureTask, PrivilegedFutureTask
- public interface Cancellable
Something, usually a task, that can be cancelled. Cancellation is
performed by the cancel method. Additional methods are
provided to determine if the task completed normally or was
cancelled.
- Since:
- 1.5
- See Also:
FutureTask
,
Executor
Method Summary |
boolean |
cancel(boolean mayInterruptIfRunning)
Attempt to cancel execution of this task. |
boolean |
isCancelled()
Returns true if this task was cancelled before it completed
normally. |
boolean |
isDone()
Returns true if this task completed. |
cancel
boolean cancel(boolean mayInterruptIfRunning)
- Attempt to cancel execution of this task. This attempt will
fail if the task has already completed, 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 interruptIfRunning parameter determines
whether the thread executing this task should be interrupted in
an attempt to stop the task.
- 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 is has already completed normally;
true otherwise
isCancelled
boolean isCancelled()
- Returns true if this task was cancelled before it completed
normally.
- Returns:
- true if 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.