com.mirth.connect.server.userutil

Class Future<V>

java.lang.Object

com.mirth.connect.server.userutil.Future<V>

All Implemented Interfaces:

Future<V>

public class Future<V>
extends Object
implements Future<V>

A 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 get when the computation has completed, blocking if necessary until it is ready. Cancellation is performed by the 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 Future for the sake of cancellability but not provide a usable result, you can declare types of the form Future<?> and return null as a result of the underlying task.

Method Summary

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

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

cancel

public 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.

Specified by:

cancel in interface Future<V>

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

public boolean isCancelled()

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

Specified by:

isCancelled in interface Future<V>

Returns:

true if this task was cancelled before it completed

isDone

public 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.

Specified by:

isDone in interface Future<V>

Returns:

true if this task completed

get

public V get()
      throws InterruptedException,
             ExecutionException

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

Specified by:

get in interface Future<V>

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

public V get(long timeoutInMillis)
      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:

timeoutInMillis - the maximum time to wait, in milliseconds

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

See Also:

get(long, TimeUnit)

get

public 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.

Specified by:

get in interface Future<V>

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