com.artemis.ComponentMapper Maven / Gradle / Ivy

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package com.artemis;

public abstract class ComponentMapper {
	/**
	 * Fast but unsafe retrieval of a component for this entity.
	 * 
	 * No bounding checks, so this could throw an
	 * {@link ArrayIndexOutOfBoundsExeption}, however in most scenarios you
	 * already know the entity possesses this component.
	 * 
	 * 
	 * @param e
	 *			the entity that should possess the component
	 *
	 * @return the instance of the component
	 *
	 * @throws ArrayIndexOutOfBoundsException
	 */
	public A get(Entity e) throws ArrayIndexOutOfBoundsException {
		return get(e.getId());
	}

	public abstract A get(int entityId) throws ArrayIndexOutOfBoundsException;

	/**
	 * Fast but unsafe retrieval of a component for this entity.
	 * 
	 * No bounding checks, so this could throw an
	 * {@link ArrayIndexOutOfBoundsExeption}, however in most scenarios you
	 * already know the entity possesses this component.
	 * 
	 *
	 * @param e
	 *			the entity that should possess the component
	 * @param forceNewInstance
	 * 			Returns a new instance of the component (only applies to {@link PackedComponent}s)
	 *
	 * @return the instance of the component
	 *
	 * @throws ArrayIndexOutOfBoundsException
	 */
	public A get(Entity e, boolean forceNewInstance) throws ArrayIndexOutOfBoundsException
	{
		return get(e.getId(), forceNewInstance);
	}

	/**
	 * Fast but unsafe retrieval of a component for this entity, by id.
	 * 
	 * No bounding checks, so this could throw an
	 * {@link ArrayIndexOutOfBoundsExeption}, however in most scenarios you
	 * already know the entity possesses this component.
	 * 
	 *
	 * @param entityId
	 *			the entity that should possess the component
	 * @param forceNewInstance
	 * 			Returns a new instance of the component (only applies to {@link PackedComponent}s)
	 *
	 * @return the instance of the component
	 *
	 * @throws ArrayIndexOutOfBoundsException
	 */
	public abstract A get(int entityId, boolean forceNewInstance) throws ArrayIndexOutOfBoundsException;

	/**
	 * Fast and safe retrieval of a component for this entity.
	 * 
	 * If the entity does not have this component then null is returned.
	 * 
	 * 
	 * @param e
	 *			the entity that should possess the component
	 *
	 * @return the instance of the component
	 */
	public A getSafe(Entity e)
	{
		return getSafe(e.getId());
	}

	/**
	 * Fast and safe retrieval of a component for this entity by id.
	 * 
	 * If the entity does not have this component then null is returned.
	 * 
	 *
	 * @param entityId
	 *			the id of entity that should possess the component
	 *
	 * @return the instance of the component
	 */
	public abstract A getSafe(int entityId);

	/**
	 * Fast and safe retrieval of a component for this entity.
	 * 
	 * If the entity does not have this component then null is returned.
	 * 
	 *
	 * @param e
	 *			the entity that should possess the component
	 * @param forceNewInstance
	 * 			If true, returns a new instance of the component (only applies to {@link PackedComponent}s)
	 *
	 * @return the instance of the component
	 */
	public A getSafe(Entity e, boolean forceNewInstance)
	{
		return getSafe(e.getId(), forceNewInstance);
	}

	/**
	 * Fast and safe retrieval of a component for this entity, by id.
	 * 
	 * If the entity does not have this component then null is returned.
	 * 
	 *
	 * @param entityId
	 *			the entity id that should possess the component
	 * @param forceNewInstance
	 * 			If true, returns a new instance of the component (only applies to {@link PackedComponent}s)
	 *
	 * @return the instance of the component
	 */
	public abstract A getSafe(int entityId, boolean forceNewInstance);

	/**
	 * Checks if the entity has this type of component.
	 *
	 * @param e
	 *			the entity to check
	 *
	 * @return true if the entity has this component type, false if it doesn't
	 */
	public boolean has(Entity e) throws ArrayIndexOutOfBoundsException
	{
		return has(e.getId());
	}

	/**
	 * Checks if the entity has this type of component.
	 *
	 * @param entityId
	 *			the id of entity to check
	 *
	 * @return true if the entity has this component type, false if it doesn't
	 */
	public abstract boolean has(int entityId);

	/**
	 * Returns a component mapper for this type of components.
	 * 
	 * @param 
	 *			the class type of components
	 * @param type
	 *			the class of components this mapper uses
	 * @param world
	 *			the world that this component mapper should use
	 *
	 * @return a new mapper
	 */
	@SuppressWarnings("unchecked")
	public static  ComponentMapper getFor(Class type, World world) {
		ComponentTypeFactory tf = world.getComponentManager().typeFactory;
		if (tf.getTypeFor(type).isPackedComponent())
			return (ComponentMapper)PackedComponentMapper.create((Class)type, world);
		else
			return new BasicComponentMapper(type, world);
	}
}