org.apache.twill.api

Class EventHandler

java.lang.Object

org.apache.twill.api.EventHandler

public abstract class EventHandler
extends Object

A callback handler for acting on application events related to TwillRunnable lifecycle events.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	EventHandler.TimeoutAction Represents action to act upon runnable launch timeout.
static class	EventHandler.TimeoutEvent This class holds information about a launch timeout event.

Field Summary

Fields

Modifier and Type	Field and Description
protected EventHandlerContext	context

Constructor Summary

Constructors

Constructor and Description
EventHandler()

Method Summary

Methods

Modifier and Type	Method and Description
EventHandlerSpecification	configure() Returns an EventHandlerSpecification for configuring this handler class.
void	destroy() Invoked by the application when shutting down.
protected Map<String,String>	getConfigs() Returns set of configurations available at runtime for access.
void	initialize(EventHandlerContext context) Invoked by the application to initialize this EventHandler instance.
abstract EventHandler.TimeoutAction	launchTimeout(Iterable<EventHandler.TimeoutEvent> timeoutEvents) Invoked when the number of expected instances doesn't match with number of actual instances.

Methods inherited from class java.lang.Object

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

Field Detail

context

protected EventHandlerContext context

Constructor Detail

EventHandler

public EventHandler()

Method Detail

configure

public EventHandlerSpecification configure()

Returns an EventHandlerSpecification for configuring this handler class.

initialize

public void initialize(EventHandlerContext context)

Invoked by the application to initialize this EventHandler instance.

Parameters:

context - context object for accessing the event handler execution context.

destroy

public void destroy()

Invoked by the application when shutting down.

launchTimeout

public abstract EventHandler.TimeoutAction launchTimeout(Iterable<EventHandler.TimeoutEvent> timeoutEvents)

Invoked when the number of expected instances doesn't match with number of actual instances.

Parameters:

timeoutEvents - An Iterable of EventHandler.TimeoutEvent that contains information about runnable launch timeout.

Returns:

A EventHandler.TimeoutAction to govern action to act.

getConfigs

protected Map<String,String> getConfigs()

Returns set of configurations available at runtime for access.