Class DefaultTaskController<InputT,OutputT>

java.lang.Object

io.aleph0.yap.core.task.DefaultTaskController<InputT,OutputT>

All Implemented Interfaces:

TaskController

Direct Known Subclasses:

DefaultConsumerTaskController, DefaultProcessorTaskController, DefaultProducerTaskController

public class DefaultTaskController<InputT,OutputT>
extends Object
implements TaskController

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	DefaultTaskController.TaskPhase	The phase of the task.
static enum	DefaultTaskController.TaskState	The internal state of a task.

Nested classes/interfaces inherited from interface io.aleph0.yap.core.task.TaskController

TaskController.ConsumerTaskControllerBuilder<InputT>, TaskController.ProcessorTaskControllerBuilder<InputT,OutputT>, TaskController.ProducerTaskControllerBuilder<OutputT>

Constructor Summary

Constructors

Constructor	Description
DefaultTaskController(int desiredConcurrency, Duration heartbeatInterval, Queue<InputT> queue, Topic<OutputT> topic)

Method Summary

Modifier and Type	Method	Description
Duration	getHeartbeatInterval()	The maximum amount of time to wait for a lifecycle event, after which TaskController.onHeartbeat() will be called.
List<TaskAction>	onCancelRequested()	Called when the user has requested to cancel this task.
List<TaskAction>	onHeartbeat()	Called when no lifecycle events have occurred within the heartbeat interval.
void	onTaskCancelled()	Called when the task has been cancelled.
void	onTaskFailed(ExecutionException e)	Called when the task has failed.
List<TaskAction>	onTaskStart()	Called when a task has been started.
void	onTaskSucceeded()	Called when the task has been successfully completed.
List<TaskAction>	onWorkerCompletedExceptionally(int id, Throwable error)	Called when a worker completed exceptionally by propagating an exception.
List<TaskAction>	onWorkerCompletedNormally(int id)	Called when a worker completed normally, for example because all input messages were processed.
List<TaskAction>	onWorkerStarted(int id)	Called when a worker was started successfully in response to a start request.
List<TaskAction>	onWorkerStopped(int id)	Called when a worker was stopped in response to a stop request.

Methods inherited from class java.lang.Object

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

Constructor Details

DefaultTaskController

public DefaultTaskController(int desiredConcurrency,
 Duration heartbeatInterval,
 Queue<InputT> queue,
 Topic<OutputT> topic)

Method Details

onTaskStart

public List<TaskAction> onTaskStart()

Description copied from interface: TaskController

Called when a task has been started. Called as the first event only.

Specified by:

onTaskStart in interface TaskController

Returns:

the next actions to perform

onWorkerStarted

public List<TaskAction> onWorkerStarted(int id)

Description copied from interface: TaskController

Called when a worker was started successfully in response to a start request.

Specified by:

onWorkerStarted in interface TaskController

Parameters:

id - the id of the worker that was started

Returns:

the next actions to perform

See Also:

• TaskAction.newStartWorkerTaskAction()

onWorkerCompletedNormally

public List<TaskAction> onWorkerCompletedNormally(int id)

Description copied from interface: TaskController

Called when a worker completed normally, for example because all input messages were processed.

Specified by:

onWorkerCompletedNormally in interface TaskController

Parameters:

id - the id of the worker that completed

Returns:

the next action to perform

onWorkerStopped

public List<TaskAction> onWorkerStopped(int id)

Description copied from interface: TaskController

Called when a worker was stopped in response to a stop request.

Specified by:

onWorkerStopped in interface TaskController

Parameters:

id - the id of the worker that was stopped

Returns:

the next action to perform

See Also:

• TaskAction.newStopWorkerTaskAction()

onWorkerCompletedExceptionally

public List<TaskAction> onWorkerCompletedExceptionally(int id,
 Throwable error)

Description copied from interface: TaskController

Called when a worker completed exceptionally by propagating an exception.

Specified by:

onWorkerCompletedExceptionally in interface TaskController

Parameters:

id - the id of the worker that completed

error - the exception that caused the worker to complete exceptionally

Returns:

the next action to perform

onCancelRequested

public List<TaskAction> onCancelRequested()

Description copied from interface: TaskController

Called when the user has requested to cancel this task. In general, this means that the controller should stop all running workers and finish the task with an appropriate status as soon as possible.

Specified by:

onCancelRequested in interface TaskController

Returns:

the next action to perform

See Also:

• TaskAction.newStopWorkerTaskAction()
• TaskAction.newCancelTask()
• TaskAction.newSucceedTask()
• TaskAction.newFailTask(ExecutionException)

onHeartbeat

public List<TaskAction> onHeartbeat()

Description copied from interface: TaskController

Called when no lifecycle events have occurred within the heartbeat interval. This ensures that the controller has periodic access to execute actions even if no lifecycle events are occurring, for example to start more workers in response to a backlog of messages, or stop workers in response to no backlog.

Specified by:

onHeartbeat in interface TaskController

Returns:

the next action to perform

onTaskSucceeded

public void onTaskSucceeded()

Description copied from interface: TaskController

Called when the task has been successfully completed. This is the last event that will be called.

Specified by:

onTaskSucceeded in interface TaskController

onTaskCancelled

public void onTaskCancelled()

Description copied from interface: TaskController

Called when the task has been cancelled. This is the last event that will be called.

Specified by:

onTaskCancelled in interface TaskController

onTaskFailed

public void onTaskFailed(ExecutionException e)

Description copied from interface: TaskController

Called when the task has failed. This is the last event that will be called.

Specified by:

onTaskFailed in interface TaskController

Parameters:

e - the exception that caused the task to fail

getHeartbeatInterval

public Duration getHeartbeatInterval()

Description copied from interface: TaskController

The maximum amount of time to wait for a lifecycle event, after which TaskController.onHeartbeat() will be called.

Specified by:

getHeartbeatInterval in interface TaskController