com.artemis

Class Aspect

java.lang.Object

com.artemis.Aspect

public class Aspect
extends Object

An Aspect is used by systems as a matcher against entities, to check if a system is interested in an entity.

Aspects define what sort of component types an entity must possess, or not possess.

This creates an aspect where an entity must possess A and B and C:
Aspect.getAspectForAll(A.class, B.class, C.class)

This creates an aspect where an entity must possess A and B and C, but must not possess U or V.
Aspect.getAspectForAll(A.class, B.class, C.class).exclude(U.class, V.class)

This creates an aspect where an entity must possess A and B and C, but must not possess U or V, but must possess one of X or Y or Z.
Aspect.getAspectForAll(A.class, B.class, C.class).exclude(U.class, V.class).one(X.class, Y.class, Z.class)

You can create and compose aspects in many ways:
Aspect.getEmpty().one(X.class, Y.class, Z.class).all(A.class, B.class, C.class).exclude(U.class, V.class)
is the same as:
Aspect.getAspectForAll(A.class, B.class, C.class).exclude(U.class, V.class).one(X.class, Y.class, Z.class)

Author:

Arni Arent

Method Summary

Methods

Modifier and Type	Method and Description
Aspect	all(Class<? extends Component>... types) Returns an aspect where an entity must possess all of the specified component types.
Aspect	all(Collection<Class<? extends Component>> types) Returns an aspect where an entity must possess all of the specified component types.
Aspect	exclude(Class<? extends Component>... types) Excludes all of the specified component types from the aspect.
Aspect	exclude(Collection<Class<? extends Component>> types) Excludes all of the specified component types from the aspect.
BitSet	getAllSet() Get a BitSet containing bits of components the entity must all possess.
static Aspect	getAspectForAll(Class<? extends Component>... types) Creates an aspect where an entity must possess all of the specified component types.
static Aspect	getAspectForOne(Class<? extends Component>... types) Creates an aspect where an entity must possess one of the specified component types.
static Aspect	getEmpty() Creates and returns an empty aspect.
BitSet	getExclusionSet() Get a BitSet containing bits of components the entity must not possess.
BitSet	getOneSet() Get a BitSet containing bits of components of which the entity must possess atleast one.
void	initialize(World world)
boolean	isInterested(BitSet componentBits) Returns whether this Aspect would accept the given set.
boolean	isInterested(Entity e) Returns whether this Aspect would accept the given Entity.
Aspect	one(Class<? extends Component>... types) Returns an aspect where an entity must possess one of the specified component types.
Aspect	one(Collection<Class<? extends Component>> types) Returns an aspect where an entity must possess one of the specified component types.

Methods inherited from class java.lang.Object

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

Method Detail

initialize

public void initialize(World world)

getAllSet

public BitSet getAllSet()

Get a BitSet containing bits of components the entity must all possess.

Returns:

the "all" BitSet

getExclusionSet

public BitSet getExclusionSet()

Get a BitSet containing bits of components the entity must not possess.

Returns:

the "exclusion" BitSet

getOneSet

public BitSet getOneSet()

Get a BitSet containing bits of components of which the entity must possess atleast one.

Returns:

the "one" BitSet

isInterested

public boolean isInterested(Entity e)

Returns whether this Aspect would accept the given Entity.

isInterested

public boolean isInterested(BitSet componentBits)

Returns whether this Aspect would accept the given set.

all

public Aspect all(Class<? extends Component>... types)

Returns an aspect where an entity must possess all of the specified component types.

Parameters:

types - a required component type

Returns:

an aspect that can be matched against entities

all

public Aspect all(Collection<Class<? extends Component>> types)

Returns an aspect where an entity must possess all of the specified component types.

Parameters:

types - a required component type

Returns:

an aspect that can be matched against entities

exclude

public Aspect exclude(Class<? extends Component>... types)

Excludes all of the specified component types from the aspect.

A system will not be interested in an entity that possesses one of the specified exclusion component types.

Parameters:

types - component type to exclude

Returns:

an aspect that can be matched against entities

exclude

public Aspect exclude(Collection<Class<? extends Component>> types)

Excludes all of the specified component types from the aspect.

A system will not be interested in an entity that possesses one of the specified exclusion component types.

Parameters:

types - component type to exclude

Returns:

an aspect that can be matched against entities

one

public Aspect one(Class<? extends Component>... types)

Returns an aspect where an entity must possess one of the specified component types.

Parameters:

types - one of the types the entity must possess

Returns:

an aspect that can be matched against entities

one

public Aspect one(Collection<Class<? extends Component>> types)

Returns an aspect where an entity must possess one of the specified component types.

Parameters:

types - one of the types the entity must possess

Returns:

an aspect that can be matched against entities

getAspectForAll

public static Aspect getAspectForAll(Class<? extends Component>... types)

Creates an aspect where an entity must possess all of the specified component types.

Parameters:

types - a required component type

Returns:

an aspect that can be matched against entities

getAspectForOne

public static Aspect getAspectForOne(Class<? extends Component>... types)

Creates an aspect where an entity must possess one of the specified component types.

Parameters:

types - one of the types the entity must possess

Returns:

an aspect that can be matched against entities

getEmpty

public static Aspect getEmpty()

Creates and returns an empty aspect.

This can be used if you want a system that processes no entities, but still gets invoked. Typical usages is when you need to create special purpose systems for debug rendering, like rendering FPS, how many entities are active in the world, etc.

You can also use the all, one and exclude methods on this aspect, so if you wanted to create a system that processes only entities possessing just one of the components A or B or C, then you can do:
Aspect.getEmpty().one(A,B,C);

Returns:

an empty Aspect that will reject all entities