org.apache.lens.server.api.events

Interface LensEventService

All Superinterfaces:

HealthCheckable, LensService

All Known Implementing Classes:

EventServiceImpl

public interface LensEventService
extends LensService

Singleton which is responsible for managing the event-listener mapping as well as processing events.

Field Summary

Fields

Modifier and Type	Field and Description
static String	NAME The Constant NAME.

Method Summary

Modifier and Type	Method and Description
<T extends LensEvent> void	addListenerForType(LensEventListener<? super T> listener, Class<T> eventType) Add a listener for the given event type.
<T extends LensEvent> Collection<LensEventListener>	getListeners(Class<T> changeType) Get all listeners of a particular type.
void	notifyEvent(LensEvent event) Process an event, and notify all listeners interested in this event.
void	notifyEventSync(LensEvent event) Process an event synchronously.
<T extends LensEvent> void	removeListener(LensEventListener<? super T> listener) Remove this listener instance from all subscribed event types.
<T extends LensEvent> void	removeListenerForType(LensEventListener<? super T> listener, Class<T> eventType) Remove listener for a given event type.

Methods inherited from interface org.apache.lens.server.api.health.HealthCheckable

getHealthStatus

Field Detail

NAME

static final String NAME

The Constant NAME.

See Also:

Constant Field Values

Method Detail

addListenerForType

<T extends LensEvent> void addListenerForType(LensEventListener<? super T> listener,
                                              Class<T> eventType)

Add a listener for the given event type. Use this method to register if the same class is expected to receive events of different types

Parameters:

listener - the listener

eventType - the event type

removeListenerForType

<T extends LensEvent> void removeListenerForType(LensEventListener<? super T> listener,
                                                 Class<T> eventType)

Remove listener for a given event type.

Parameters:

listener - the listener

eventType - the event type

removeListener

<T extends LensEvent> void removeListener(LensEventListener<? super T> listener)

Remove this listener instance from all subscribed event types.

Parameters:

listener - the listener

notifyEvent

void notifyEvent(LensEvent event)
          throws LensException

Process an event, and notify all listeners interested in this event.

Parameters:

event - object

Throws:

LensException - the lens exception

getListeners

<T extends LensEvent> Collection<LensEventListener> getListeners(Class<T> changeType)

Get all listeners of a particular type.

Parameters:

changeType - the change type

Returns:

all the listeners

notifyEventSync

void notifyEventSync(LensEvent event)
              throws LensException

Process an event synchronously. It does not return until the processing is finished.

Parameters:

event -

Throws:

LensException