com.badlogic.ashley.core

Class Engine

java.lang.Object

com.badlogic.ashley.core.Engine

Direct Known Subclasses:

PooledEngine

public class Engine
extends java.lang.Object

The heart of the Entity framework. It is responsible for keeping track of Entity and managing EntitySystem objects. The Engine should be updated every tick via the update(float) method. With the Engine you can:

• Add/Remove Entity objects
• Add/Remove EntitySystems
• Obtain a list of entities for a specific Family
• Update the main loop
• Register/unregister EntityListener objects

Constructor Summary

Constructors

Constructor and Description
Engine()

Method Summary

Modifier and Type	Method and Description
void	addEntity(Entity entity) Adds an entity to this Engine.
protected void	addEntityInternal(Entity entity)
void	addEntityListener(EntityListener listener) Adds an EntityListener.
void	addEntityListener(Family family, EntityListener listener) Adds an EntityListener for a specific Family.
void	addEntityListener(Family family, int priority, EntityListener listener) Adds an EntityListener for a specific Family.
void	addEntityListener(int priority, EntityListener listener) Adds an EntityListener.
void	addSystem(EntitySystem system) Adds the EntitySystem to this Engine.
<T extends Component> T	createComponent(java.lang.Class<T> componentType) Creates a new Component.
Entity	createEntity() Creates a new Entity object.
ImmutableArray<Entity>	getEntities() Returns an ImmutableArray of Entity that is managed by the the Engine but cannot be used to modify the state of the Engine.
ImmutableArray<Entity>	getEntitiesFor(Family family) Returns immutable collection of entities for the specified Family.
<T extends EntitySystem> T	getSystem(java.lang.Class<T> systemType) Quick EntitySystem retrieval.
ImmutableArray<EntitySystem>	getSystems()
void	removeAllEntities() Removes all entities registered with this Engine.
void	removeAllEntities(Family family) Removes all entities of the given Family.
void	removeAllSystems() Removes all systems from this Engine.
void	removeEntity(Entity entity) Removes an entity from this Engine.
protected void	removeEntityInternal(Entity entity)
void	removeEntityListener(EntityListener listener) Removes an EntityListener
void	removeSystem(EntitySystem system) Removes the EntitySystem from this Engine.
void	update(float deltaTime) Updates all the systems in this Engine.

Methods inherited from class java.lang.Object

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

Constructor Detail

Engine

public Engine()

Method Detail

createEntity

public Entity createEntity()

Creates a new Entity object.

Returns:

@Entity

createComponent

public <T extends Component> T createComponent(java.lang.Class<T> componentType)

Creates a new Component. To use that method your components must have a visible no-arg constructor

addEntity

public void addEntity(Entity entity)

Adds an entity to this Engine. This will throw an IllegalArgumentException if the given entity was already registered with an engine.

removeEntity

public void removeEntity(Entity entity)

Removes an entity from this Engine.

removeAllEntities

public void removeAllEntities(Family family)

Removes all entities of the given Family.

removeAllEntities

public void removeAllEntities()

Removes all entities registered with this Engine.

getEntities

public ImmutableArray<Entity> getEntities()

Returns an ImmutableArray of Entity that is managed by the the Engine but cannot be used to modify the state of the Engine. This Array is not Immutable in the sense that its contents will not be modified, but in the sense that it only reflects the state of the engine. The Array is Immutable in the sense that you cannot modify its contents through the API of the ImmutableArray class, but is instead "Managed" by the Engine itself. The engine may add or remove items from the array and this will be reflected in the returned array. This is an important note if you are looping through the returned entities and calling operations that may add/remove entities from the engine, as the underlying iterator of the returned array will reflect these modifications. The returned array will have entities removed from it if they are removed from the engine, but there is no way to introduce new Entities through the array's interface, or remove entities from the engine through the array interface. Discussion of this can be found at https://github.com/libgdx/ashley/issues/224

Returns:

An unmodifiable array of entities that will match the state of the entities in the engine.

addSystem

public void addSystem(EntitySystem system)

Adds the EntitySystem to this Engine. If the Engine already had a system of the same class, the new one will replace the old one.

removeSystem

public void removeSystem(EntitySystem system)

Removes the EntitySystem from this Engine.

removeAllSystems

public void removeAllSystems()

Removes all systems from this Engine.

getSystem

public <T extends EntitySystem> T getSystem(java.lang.Class<T> systemType)

Quick EntitySystem retrieval.

getSystems

public ImmutableArray<EntitySystem> getSystems()

Returns:

immutable array of all entity systems managed by the Engine.

getEntitiesFor

public ImmutableArray<Entity> getEntitiesFor(Family family)

Returns immutable collection of entities for the specified Family. Returns the same instance every time for the same Family.

addEntityListener

public void addEntityListener(EntityListener listener)

Adds an EntityListener. The listener will be notified every time an entity is added/removed to/from the engine.

addEntityListener

public void addEntityListener(int priority,
                              EntityListener listener)

Adds an EntityListener. The listener will be notified every time an entity is added/removed to/from the engine. The priority determines in which order the entity listeners will be called. Lower value means it will get executed first.

addEntityListener

public void addEntityListener(Family family,
                              EntityListener listener)

Adds an EntityListener for a specific Family. The listener will be notified every time an entity is added/removed to/from the given family.

addEntityListener

public void addEntityListener(Family family,
                              int priority,
                              EntityListener listener)

Adds an EntityListener for a specific Family. The listener will be notified every time an entity is added/removed to/from the given family. The priority determines in which order the entity listeners will be called. Lower value means it will get executed first.

removeEntityListener

public void removeEntityListener(EntityListener listener)

Removes an EntityListener

update

public void update(float deltaTime)

Updates all the systems in this Engine.

Parameters:

deltaTime - The time passed since the last frame.

addEntityInternal

protected void addEntityInternal(Entity entity)

removeEntityInternal

protected void removeEntityInternal(Entity entity)