org.jppf.node.protocol

Interface Task<T>

Type Parameters:

T - the type of results produced by the task.

All Superinterfaces:

Runnable, Serializable

All Known Implementing Classes:

CommandLineTask, DemoTask, HelloTask, JPPFAnnotatedTask, JPPFExceptionResult, JPPFTask

public interface Task<T>
extends Runnable, Serializable

Interface for all tasks submitted to the execution server.

Method Summary

Methods

Modifier and Type	Method and Description
<V> V	compute(JPPFCallable<V> callable) Compute a value on the client-side, as the result of the execution of a JPPFCallable.
DataProvider	getDataProvider() Get the provider of shared data for this task.
Exception	getException() Get the exception that was raised by this task's execution.
String	getId() Get the user-assigned id for this task.
int	getPosition() Returns the position of this task in the job in which it was submitted.
T	getResult() Get the result of the task execution.
Object	getTaskObject() Get the JPPFRunnable-annotated object or POJO wrapped by this task.
JPPFSchedule	getTimeoutSchedule() Get the task timeout schedule configuration.
boolean	isInNode() Determine whether this task is executing within a node, or locally on the client side.
void	onCancel() Callback invoked when this task is cancelled.
void	onRestart() Deprecated. the task restart feature is inherently unsafe, as it depends on the task having a unique id among all the tasks running in the grid, which cannot be guaranteed. This feature has been removed from the management APIs, with no replacement.
void	onTimeout() Callback invoked when this task times out.
void	setDataProvider(DataProvider dataProvider) Set the provider of shared data for this task.
void	setException(Exception exception) Sets the exception that was raised by this task's execution in the run method.
void	setId(String id) Set the user-assigned id for this task.
void	setPosition(int position) Set the position of this task in the job in which it was submitted.
void	setResult(T result) Set the result of the task execution.
void	setTimeoutSchedule(JPPFSchedule timeoutSchedule) Get the task timeout schedule configuration.

Methods inherited from interface java.lang.Runnable

run

Method Detail

getResult

T getResult()

Get the result of the task execution.

Returns:

the result as an array of bytes.

setResult

void setResult(T result)

Set the result of the task execution.

Parameters:

result - the result of this task's execution.

getException

Exception getException()

Get the exception that was raised by this task's execution. If the task raised a Throwable, the exception is embedded into a JPPFException.

Returns:

a Exception instance, or null if no exception was raised.

setException

void setException(Exception exception)

Sets the exception that was raised by this task's execution in the run method. The exception is set by the JPPF framework.

Parameters:

exception - a ClientApplicationException instance.

getDataProvider

DataProvider getDataProvider()

Get the provider of shared data for this task.

Returns:

a DataProvider instance.

setDataProvider

void setDataProvider(DataProvider dataProvider)

Set the provider of shared data for this task.

Parameters:

dataProvider - a DataProvider instance.

getId

String getId()

Get the user-assigned id for this task.

Returns:

the id as a string.

setId

void setId(String id)

Set the user-assigned id for this task.

Parameters:

id - the id as a string.

onCancel

void onCancel()

Callback invoked when this task is cancelled. The default implementation does nothing and should be overriden by subclasses that desire to implement a specific behaviour on cancellation.

onRestart

void onRestart()

Deprecated. the task restart feature is inherently unsafe, as it depends on the task having a unique id among all the tasks running in the grid, which cannot be guaranteed. This feature has been removed from the management APIs, with no replacement.

Callback invoked when this task is restarted. The default implementation does nothing and should be overriden by subclasses that desire to implement a specific behaviour on restart.

onTimeout

void onTimeout()

Callback invoked when this task times out. The default implementation does nothing and should be overriden by subclasses that desire to implement a specific behaviour on timeout.

getTaskObject

Object getTaskObject()

Get the JPPFRunnable-annotated object or POJO wrapped by this task.

Returns:

an object or class that is JPPF-annotated.

getTimeoutSchedule

JPPFSchedule getTimeoutSchedule()

Get the task timeout schedule configuration.

Returns:

a JPPFSchedule instance.

setTimeoutSchedule

void setTimeoutSchedule(JPPFSchedule timeoutSchedule)

Get the task timeout schedule configuration.

Parameters:

timeoutSchedule - a JPPFSchedule instance.

getPosition

int getPosition()

Returns the position of this task in the job in which it was submitted.

Returns:

the position of this task as an int.

setPosition

void setPosition(int position)

Set the position of this task in the job in which it was submitted.

Parameters:

position - the position of this task as an int.

isInNode

boolean isInNode()

Determine whether this task is executing within a node, or locally on the client side.

Returns:

true if this task is executing in a node, false if it is on the client side.

compute

<V> V compute(JPPFCallable<V> callable)
          throws Exception

Compute a value on the client-side, as the result of the execution of a JPPFCallable.

Any Throwable raised in the callable's call() method will be thrown as the result of this method. If the Throwable is an instance of Exception or one of its subclasses, it is thrown as such, otherwise it is wrapped into a JPPFException.

Type Parameters:

V - the type of results returned by the callable.

Parameters:

callable - the callable to execute on the client side.

Returns:

the value computed on the client, or null if the value could not be computed.

Throws:

Exception - if the execution of the callable in the client resulted in a Throwable being raised.

See Also:

JPPFCallable