GridTaskFuture (GridGain 2.1.0 API)

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GridGain™ 2.1.0
Java API Specification

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org.gridgain.grid
Interface GridTaskFuture<R>


Type Parameters:: R - Type of the task result returning from GridTask.reduce(java.util.List) method.

@Apache20LicenseCompatible public interface GridTaskFuture<R>

This class defines a handler for asynchronous task execution. It's similar in design to standard JDK Future interface. Instance of this interface is returned from the following methods:

In GridGain 2.0 this interface API has been updated for better static type checking. Although the change is trivial and provides much better type safety during development - it introduced incompatibility with prior versions of GridGain. Follow this link for easy source code migration instructions.

Method Summary
`void`	`cancel()` Cancels this task.
`R`	`get()` Synchronously waits for task completion and returns task computation result.
`R`	`get(long timeout)` Synchronously waits if necessary for at most the given time for task completion and returns task computation result.
`GridTaskSession`	`getTaskSession()` Gets task session of execution grid task.
`boolean`	`isCancelled()` Returns `true` if this task was cancelled before it completed normally.
`boolean`	`isDone()` Checks if task is finished.

getTaskSession

GridTaskSession getTaskSession()

Gets task session of execution grid task.

Returns:: Task session.

get

R get()
      throws GridTaskTimeoutException,
             GridException

Synchronously waits for task completion and returns task computation result. If task computation caused an exception, then it gets thrown out of this method.

Throws:: GridTaskTimeoutException - If task execution has timed out. Note that physically task may still be executing, as there is no practical way to stop it (however, every job within task will receive interrupt call).; GridException - If task execution resulted in exception.
Returns:: Task computation result.

get

R get(long timeout)
      throws GridTaskTimeoutException,
             GridException

Synchronously waits if necessary for at most the given time for task completion and returns task computation result. If task computation caused an exception, then it gets thrown out of this method.

Throws:: GridTaskTimeoutException - If task execution has timed out. Note that physically task may still be executing, as there is no practical way to stop it (however, every job within task will receive interrupt call).; GridException - If task execution resulted in exception.
Parameters:: timeout - The maximum timeout in milliseconds.
Returns:: Task computation result.

cancel

void cancel()
            throws GridException

Cancels this task.

Note, that there is no guarantee that a task will be cancelled after invoking this method. Implementation will attempt to cancel all jobs spawned by this task by calling GridJob.cancel(), but it is up to the actual GridJob implementation to react on it and cancel the execution. There is also no guarantee that every job spawned by the task will get the cancellation request, especially if a job was traveling on the network at the time the cancel request was issued.

Throws:: GridException - If task cancellation request was not successfully sent to all participating nodes.

isDone

boolean isDone()

Checks if task is finished.

Returns:: true if task is finished, false 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 normally.