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 {@code cancel} is called, this task should never run. If the task has already started, then the {@code mayInterruptIfRunning} parameter determines whether the thread executing this task should be interrupted in an attempt to stop the task.
Waits if necessary for the computation to complete, and then retrieves its result.
Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available.
Returns {@code true} if this task was cancelled before it completed normally.
Returns {@code true} if this task completed.
A {@code Future} represents the result of an asynchronous computation. Methods are provided to check if the computation is complete, to wait for its completion, and to retrieve the result of the computation. The result can only be retrieved using method {@code get} when the computation has completed, blocking if necessary until it is ready. Cancellation is performed by the {@code cancel} method. Additional methods are provided to determine if the task completed normally or was cancelled. Once a computation has completed, the computation cannot be cancelled. If you would like to use a {@code Future} for the sake of cancellability but not provide a usable result, you can declare types of the form {@code Future!T} and return {@code null} as a result of the underlying task.