Package org.apache.hadoop.yarn.event

Class EventDispatcher<T extends Event>

java.lang.Object

org.apache.hadoop.service.AbstractService

org.apache.hadoop.yarn.event.EventDispatcher<T>

Type Parameters:

T - Type of Event

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, org.apache.hadoop.service.Service, EventHandler<T>

public class EventDispatcher<T extends Event>
extends org.apache.hadoop.service.AbstractService
implements EventHandler<T>

This is a specialized EventHandler to be used by Services that are expected handle a large number of events efficiently by ensuring that the caller thread is not blocked. Events are immediately stored in a BlockingQueue and a separate dedicated Thread consumes events from the queue and handles appropriately

Nested Class Summary

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

org.apache.hadoop.service.Service.STATE

Constructor Summary

Constructors

Constructor	Description
EventDispatcher(EventHandler<T> handler, java.lang.String name)

Method Summary

Modifier and Type	Method	Description
void	disableExitOnError()
protected long	getEventProcessorId()
int	getEventQueueSize()
void	handle(T event)
protected boolean	isStopped()
protected void	serviceStart()
protected void	serviceStop()
void	setMetrics(EventTypeMetrics metrics)

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

Constructor Detail

EventDispatcher

public EventDispatcher(EventHandler<T> handler,
                       java.lang.String name)

Method Detail

serviceStart

protected void serviceStart()
                     throws java.lang.Exception

Overrides:

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

Throws:

java.lang.Exception

serviceStop

protected void serviceStop()
                    throws java.lang.Exception

Overrides:

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

Throws:

java.lang.Exception

handle

public void handle(T event)

Specified by:

handle in interface EventHandler<T extends Event>

disableExitOnError

@VisibleForTesting
public void disableExitOnError()

setMetrics

public void setMetrics(EventTypeMetrics metrics)

getEventProcessorId

protected long getEventProcessorId()

isStopped

protected boolean isStopped()

getEventQueueSize

public int getEventQueueSize()