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

Methods

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.
<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