Package com.j3d.engine.react.events

package com.j3d.engine.react.events

Holds all subclasses and interfaces related to the event system.

Events

The engine, in most cases instead of trying to finder a specific class instance and method to call, makes use of "events" which allow any parts of the engine to fire events to any other part at any time of execution.

Any class which extends EventEmitter inherits event emitting capabilities to any class which it attaches that implements EventListener. Classes which cannot directly extends EventEmitter can instead implement EventEmitterInterface and hence use the generic static utilities provided by EventEmitter such as to still emit events.

An event is broadcast with an EventPayload to all attached listeners. This class can also be the superclass of concrete implementations, and it's up to the listener to decipher the payload. However, there is also a EventType enum where all event types can be categorised by a single enum before performing type casting.

Classes and interfaces

• An EventEmitter is a class that allows other classes to register as listeners and receive events.

  The EventEmitterInterface is an interface that allows classes that cannot extend EventEmitter to still emit events using its static utility methods.

• An EventListener is an interface which defines any class as one that can listen for events and handle said events via EventListener.onEvent(com.j3d.engine.react.events.EventType, com.j3d.engine.react.events.EventPayload)

  An EventReactor is a special type of EventListener which is removed after it has received it's event. It "reacts" to the event once and is removed thereafter.

  An IdempotentEventListener is a special type of EventListener that guarantees that processing the same event multiple times will produce the same result as processing it once. This is useful for events that might be re-triggered or re-broadcast, ensuring consistent state.

• An EventPayload is a class that carries data related to an event. It can be extended to provide specific event data.
• An EventType is an enum that categorises different types of events, allowing listeners to filter and handle specific event types.

Author:

Lehlogonolo Poole

Related Packages

Package	Description
com.j3d.engine.react	Includes sub-packages for any systems which "react" to incoming data or otherwise store this type of reaction in a meaningful way.
com.j3d.engine.react.events.payloads	Every single implementation of EventPayload.
com.j3d.engine.react.actions	Stores all Undo/Redo related classes, labelled as "Actions"
com.j3d.engine.react.history	Package that encapsules all history related classes

Class	Description
EventEmitter	EventEmitter is a class that allows for other classes to attach events that they can broadcast to at any time.
EventEmitterInterface	EventEmitterInterface is an interface that allows for other classes to attach events that they can broadcast to at any time.
EventListener	EventListener is an interface which just allows Objects to listen for incoming Events at any time.
EventPayload<T>	EventPayload is an abstract class which is used to represent the properties that the called event may input and or return.
EventReactor	An interface which only reacts to a single event and later gets removed.
EventType	Events is an enum that describes the possible Events that a listener can listen for.
IdempotentEventListener<T extends EventPayload<?>,V>	A simple interface for implementors to use such that they dont bloat some specific setting due to multiple events firing that do the same thing.