com.brightcove.player.event

Class RegisteringEventEmitter

java.lang.Object

com.brightcove.player.event.RegisteringEventEmitter

All Implemented Interfaces:

EventEmitter

public class RegisteringEventEmitter
extends java.lang.Object
implements EventEmitter

The RegisteringEventEmitter allows developers to constrain which events their Components are intended to listen for and emit. If a component attempts to emit or listen for an event that it hasn't explicitly listed, an exception will be thrown.

Registration occurs by creating a new instance of RegisteringEventEmitter, using a shared EventEmitter (typically EventEmitterImpl), and the class to be registered. The class in question MUST be decorated with two annotations: ListensFor and Emits. Each takes a String[], populated with EventType strings, attached to their 'events' property. Each annotation MUST be included, even if the component has no intention of listening or emitting any events.

For example, the following component class declartion:

@Emits(events = {EventType.PLAY, EventType.STOP})
@ListensFor(events = {EventType.PLAY})
public class SampleComponent implements Component

See Also:

EventEmitter, EventEmitterImpl, Component, Emits, ListensFor

Constructor Summary

Constructors

Constructor and Description
RegisteringEventEmitter(EventEmitter emitter, java.lang.Class<? extends Component> component) Main constructor.

Method Summary

Modifier and Type	Method and Description
static RegisteringEventEmitter	build(EventEmitter incomingEmitter, java.lang.Class<? extends Component> componentClass) Factory method to create a new RegisteringEventEmitter given an existing EventEmitter and a Component implementation.
protected java.util.List<java.lang.String>	convertEventsFromAnnotation(java.lang.Class<? extends Component> componentClass, java.lang.Class<? extends java.lang.annotation.Annotation> annotationClass) Convenience method on BaseComponent which converts the eventTypes in the ListensFor or Emits annotations to a List of event names for ease of use.
void	disable() Disables listener registration and event emitting.
void	emit(java.lang.String eventType) Emits an Event of EventType.
void	emit(java.lang.String eventType, java.util.Map<java.lang.String,java.lang.Object> properties) Emits and Event of EventType, provided the Component is allowed to do so.
void	enable() Enables listener registration and event emitting.
java.util.List<java.lang.String>	getAllowedEmittedEvents() Retrieves a list of all Events that are allowed to be emitted in this RegisteringEventEmitter.
java.util.List<java.lang.String>	getAllowedListenEvents() Retrieves a list of all Events that are allowed to be listened in this RegisteringEventEmitter.
EventEmitter	getRootEmitter() Retrieve the underlying EventEmitter provided when initializing this emitter.
void	off() Remove all listeners.
void	off(java.lang.String eventType, int token) Remove a listener from handling an event of EventType.
int	on(java.lang.String eventType, EventListener listener) Add a listener for an EventType, filtered by what the component is allowed to listen for.
int	once(java.lang.String eventType, EventListener listener) Add a listener for an EventType, filtered by what the component is allowed to listen for.
void	request(java.lang.String eventType, EventListener listener) Requests a response from the first listener to respond.
void	request(java.lang.String eventType, java.util.Map<java.lang.String,java.lang.Object> properties, EventListener listener) Requests a response from the first listener to respond.
void	respond(Event event) Respond to a request.
void	respond(java.util.Map<java.lang.String,java.lang.Object> properties) Respond to a request.

Methods inherited from class java.lang.Object

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

Constructor Detail

RegisteringEventEmitter

public RegisteringEventEmitter(EventEmitter emitter,
                               java.lang.Class<? extends Component> component)
                        throws java.lang.IllegalArgumentException

Main constructor. Requires both an emitter and component. Will throw an IllegalArgumentException if either is missing.

Parameters:

emitter -

component -

Throws:

java.lang.IllegalArgumentException

Method Detail

getAllowedEmittedEvents

public java.util.List<java.lang.String> getAllowedEmittedEvents()

Retrieves a list of all Events that are allowed to be emitted in this RegisteringEventEmitter.

Returns:

a List of EventType strings for all allowed emits

getAllowedListenEvents

public java.util.List<java.lang.String> getAllowedListenEvents()

Retrieves a list of all Events that are allowed to be listened in this RegisteringEventEmitter.

Returns:

a List of EventType strings for all allowed listened events

on

public int on(java.lang.String eventType,
              EventListener listener)

Add a listener for an EventType, filtered by what the component is allowed to listen for. The response token should be cached by component for use later in the component lifecycle

Specified by:

on in interface EventEmitter

Parameters:

eventType -

listener -

Returns:

an empty string if listener was not attached, a UUID in string form if was successfully attached

See Also:

EventListener

once

public int once(java.lang.String eventType,
                EventListener listener)

Add a listener for an EventType, filtered by what the component is allowed to listen for. This listener will be handled only once, at which point it is removed. The response token should be cached by component for use later in the component lifecycle

Specified by:

once in interface EventEmitter

Parameters:

eventType -

listener -

Returns:

an empty string if listener was not attached, a UUID in string form if was successfully attached

See Also:

EventListener

off

public void off()

Remove all listeners.

Specified by:

off in interface EventEmitter

off

public void off(java.lang.String eventType,
                int token)

Remove a listener from handling an event of EventType. Requires a token given by on() or once()

Specified by:

off in interface EventEmitter

Parameters:

eventType -

token -

emit

public void emit(java.lang.String eventType)

Emits an Event of EventType. However, the Event will only be emitted if the component is allowed to do so

Specified by:

emit in interface EventEmitter

Parameters:

eventType -

emit

public void emit(java.lang.String eventType,
                 java.util.Map<java.lang.String,java.lang.Object> properties)

Emits and Event of EventType, provided the Component is allowed to do so. Will also pass along a set of String properties.

Specified by:

emit in interface EventEmitter

Parameters:

eventType -

properties -

getRootEmitter

public EventEmitter getRootEmitter()

Retrieve the underlying EventEmitter provided when initializing this emitter.

Returns:

the root EventEmitter

build

public static RegisteringEventEmitter build(EventEmitter incomingEmitter,
                                            java.lang.Class<? extends Component> componentClass)

Factory method to create a new RegisteringEventEmitter given an existing EventEmitter and a Component implementation. All RegisteringEventEmitters should be created with this method.

Parameters:

incomingEmitter - an existing EventEmitter, could also be a RegisteringEventEmitter

componentClass - the Component implementation to be managed by this emitter

Returns:

a properly initialized RegisteringEventEmitter

request

public void request(java.lang.String eventType,
                    EventListener listener)

Requests a response from the first listener to respond. The response is handled by the provided listener, after which the listener is removed.

Specified by:

request in interface EventEmitter

Parameters:

eventType - The type of Event to emit and expect a response from

listener - A listener to process the response. After processing, the response should be removed

See Also:

EventListener, EventType

request

public void request(java.lang.String eventType,
                    java.util.Map<java.lang.String,java.lang.Object> properties,
                    EventListener listener)

Requests a response from the first listener to respond. The response is handled by the provided listener, after which the listener is removed. The provided properties map is passed on to the responding listener

Specified by:

request in interface EventEmitter

Parameters:

eventType - The type of Event to emit and expect a response from

properties - A Map of properties to pass along the event chain

listener - A listener to process the response. After processing, the response should be removed

See Also:

EventListener, EventType

respond

public void respond(java.util.Map<java.lang.String,java.lang.Object> properties)

Respond to a request. Should be placed within an EventListener and via some means (e.g. the token of an InvocationContainer) know which Request Listener to respond to. See

Specified by:

respond in interface EventEmitter

Parameters:

properties -

respond

public void respond(Event event)

Respond to a request. Should be called within an EventListener and given an Event object with the appropriate REQUEST_TOKEN value

Specified by:

respond in interface EventEmitter

Parameters:

event - an Event object with, at minimum, the necessary REQUEST_TOKEN value

enable

public void enable()

Enables listener registration and event emitting.

Specified by:

enable in interface EventEmitter

disable

public void disable()

Disables listener registration and event emitting.

Specified by:

disable in interface EventEmitter

convertEventsFromAnnotation

protected java.util.List<java.lang.String> convertEventsFromAnnotation(java.lang.Class<? extends Component> componentClass,
                                                                       java.lang.Class<? extends java.lang.annotation.Annotation> annotationClass)

Convenience method on BaseComponent which converts the eventTypes in the ListensFor or Emits annotations to a List of event names for ease of use.

Parameters:

componentClass - The component's class.

annotationClass - The annotation's class.

Returns:

A list of event names.