org.apache.slider.server.services.workflow

Class WorkflowCallbackService<V>

java.lang.Object

org.apache.hadoop.service.AbstractService

org.apache.slider.server.services.workflow.WorkflowExecutorService<E>

org.apache.slider.server.services.workflow.WorkflowScheduledExecutorService<ScheduledExecutorService>

org.apache.slider.server.services.workflow.WorkflowCallbackService<V>

All Implemented Interfaces:

Closeable, AutoCloseable, org.apache.hadoop.service.Service

public class WorkflowCallbackService<V>
extends WorkflowScheduledExecutorService<ScheduledExecutorService>

A service that calls the supplied callback when it is started -after the given delay. It can be configured to stop itself after the callback has completed, marking any exception raised as the exception of this service. The notifications come in on a callback thread -a thread that is only started in this service's start() operation.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.hadoop.service.Service

org.apache.hadoop.service.Service.STATE

Field Summary

Fields

Modifier and Type	Field and Description
protected static org.slf4j.Logger	LOG

Constructor Summary

Constructors

Constructor and Description
WorkflowCallbackService(String name, Callable<V> callback, int delay, boolean terminate) Create an instance of the service

Method Summary

Methods

Modifier and Type	Method and Description
Exception	getCallbackException() Get the exception raised by a callback.
ScheduledFuture<V>	getScheduledFuture()
protected void	serviceStart()
protected void	serviceStop() Stop the service.

Methods inherited from class org.apache.slider.server.services.workflow.WorkflowExecutorService

execute, getExecutor, setExecutor, stopExecutor, submit

Methods inherited from class org.apache.hadoop.service.AbstractService

close, getBlockers, getConfig, getFailureCause, getFailureState, getLifecycleHistory, getName, getServiceState, getStartTime, init, isInState, noteFailure, putBlocker, registerGlobalListener, registerServiceListener, removeBlocker, serviceInit, setConfig, start, stop, toString, unregisterGlobalListener, unregisterServiceListener, waitForServiceToStop

Methods inherited from class java.lang.Object

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

Field Detail

LOG

protected static final org.slf4j.Logger LOG

Constructor Detail

WorkflowCallbackService

public WorkflowCallbackService(String name,
                       Callable<V> callback,
                       int delay,
                       boolean terminate)

Create an instance of the service

Parameters:

name - service name

callback - callback to invoke

delay - delay -or 0 for no delay

terminate - terminate this service after the callback?

Method Detail

getScheduledFuture

public ScheduledFuture<V> getScheduledFuture()

serviceStart

protected void serviceStart()
                     throws Exception

Overrides:

serviceStart in class org.apache.hadoop.service.AbstractService

Throws:

Exception

serviceStop

protected void serviceStop()
                    throws Exception

Stop the service. If there is any exception noted from any executed notification, note the exception in this class

Overrides:

serviceStop in class WorkflowExecutorService<ScheduledExecutorService>

Throws:

Exception - exception.

getCallbackException

public Exception getCallbackException()

Get the exception raised by a callback. Will always be null if the callback has not been executed; will only be non-null after any success.

Returns:

a callback