ai.grakn.engine.tasks

Class BackgroundTask

java.lang.Object

ai.grakn.engine.tasks.BackgroundTask

Direct Known Subclasses:

MockBackgroundTask, PostProcessingTask

public abstract class BackgroundTask
extends Object

Interface which all tasks that wish to be scheduled for later execution as background tasks must implement.

Author:

Denis Lobanov

Constructor Summary

Constructors

Constructor and Description
BackgroundTask()

Method Summary

Modifier and Type	Method and Description
TaskConfiguration	configuration()
GraknConfig	engineConfiguration()
EngineGraknTxFactory	factory()
void	initialize(TaskConfiguration configuration, GraknConfig engineConfig, EngineGraknTxFactory factory, com.codahale.metrics.MetricRegistry metricRegistry, PostProcessor postProcessor) Initialize the BackgroundTask.
com.codahale.metrics.MetricRegistry	metricRegistry()
PostProcessor	postProcessor()
abstract boolean	start() Called to start execution of the task, may be called on a newly scheduled or previously stopped task.
boolean	stop() Called to stop execution of the task, may be called on a running or paused task.

Methods inherited from class java.lang.Object

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

Constructor Detail

BackgroundTask

public BackgroundTask()

Method Detail

initialize

public final void initialize(TaskConfiguration configuration,
                             GraknConfig engineConfig,
                             EngineGraknTxFactory factory,
                             com.codahale.metrics.MetricRegistry metricRegistry,
                             PostProcessor postProcessor)

Initialize the BackgroundTask. This must be called prior to any other call to BackgroundTask.

Parameters:

configuration - The configuration needed to execute the task

metricRegistry - Metric registry

start

public abstract boolean start()

Called to start execution of the task, may be called on a newly scheduled or previously stopped task.

Returns:

true if the task successfully completed, or false if it was stopped.

stop

public boolean stop()

Called to stop execution of the task, may be called on a running or paused task. Task should stop gracefully.

This implementation always throws UnsupportedOperationException.

Returns:

true if the task was successfully stopped, or false if it could not be stopped.

Throws:

UnsupportedOperationException - if stopping the task is not supported TODO: Should we allow start() to be called after stop()?

configuration

public final TaskConfiguration configuration()

engineConfiguration

public final GraknConfig engineConfiguration()

factory

public final EngineGraknTxFactory factory()

metricRegistry

public final com.codahale.metrics.MetricRegistry metricRegistry()

postProcessor

public final PostProcessor postProcessor()