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

Modifier and Type	Method and Description
void	aborted() Invoked by the application when the application is aborted because of timeout.
void	completed() Invoked by the application when all containers complete.
EventHandlerSpecification	configure() Returns an EventHandlerSpecification for configuring this handler class.
void	containerLaunched(String runnableName, int instanceId, String containerId) Invoked by the application when new container is launched for a TwillRunnable.
void	containerStopped(String runnableName, int instanceId, String containerId, int exitStatus) Invoked by the application when the container allocated for a TwillRunnable is stopped.
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.
void	killed() Invoked by the application when stop command is received to kill the current application.
EventHandler.TimeoutAction	launchTimeout(Iterable<EventHandler.TimeoutEvent> timeoutEvents) Invoked when the number of expected instances doesn't match with number of actual instances.
void	started() Invoked by the application when it starts.

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.

started

public void started()

Invoked by the application when it starts.

containerLaunched

public void containerLaunched(String runnableName,
                              int instanceId,
                              String containerId)

Invoked by the application when new container is launched for a TwillRunnable.

Parameters:

runnableName - name of the runnable to be run in the new container

instanceId - the instance ID of the runnable instance to be run in the new container

containerId - the ID of the newly launched container

containerStopped

public void containerStopped(String runnableName,
                             int instanceId,
                             String containerId,
                             int exitStatus)

Invoked by the application when the container allocated for a TwillRunnable is stopped.

Parameters:

runnableName - name of the runnable in the stopped container

instanceId - the instance ID of the runnable instance run in the stopped container

containerId - the ID of the stopped container

exitStatus - the exit status of the container

completed

public void completed()

Invoked by the application when all containers complete.

killed

public void killed()

Invoked by the application when stop command is received to kill the current application.

aborted

public void aborted()

Invoked by the application when the application is aborted because of timeout.

destroy

public void destroy()

Invoked by the application when shutting down.

launchTimeout

public 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. By default it is to recheck after 60 seconds.

getConfigs

protected Map<String,String> getConfigs()

Returns set of configurations available at runtime for access.