Struct EntityRef

pub struct EntityRef<'a> { /* private fields */ }

Handle to an entity with any component types

Implementations

impl<'a> EntityRef<'a>

pub fn entity(&self) -> Entity

Get the Entity handle associated with this entity

pub fn satisfies<Q>(&self) -> bool

where Q: Query,

Determine whether this entity would satisfy the query Q

pub fn has<T>(&self) -> bool

where T: Component,

Determine whether this entity has a T component without borrowing it

Equivalent to satisfies::<&T>

pub fn get<T>(&self) -> Option<<T as ComponentRef<'a>>::Ref>

where T: ComponentRef<'a>,

Borrow a single component, if it exists

T must be a shared or unique reference to a component type.

Example

let mut world = World::new();
let a = world.spawn((42, "abc"));
let e = world.entity(a).unwrap();
*e.get::<&mut i32>().unwrap() = 17;
assert_eq!(*e.get::<&i32>().unwrap(), 17);

Panics if T is a unique reference and the component is already borrowed, or if the component is already uniquely borrowed.

pub fn query<Q>(&self) -> QueryOne<'a, Q>

where Q: Query,

Run a query against this entity

Equivalent to invoking World::query_one on the entity. May outlive self.

Example

let mut world = World::new();
let a = world.spawn((123, true, "abc"));
// The returned query must outlive the borrow made by `get`
let mut query = world.entity(a).unwrap().query::<(&mut i32, &bool)>();
let (mut number, flag) = query.get().unwrap();
if *flag { *number *= 2; }
assert_eq!(*number, 246);

pub fn component_types(&self) -> impl Iterator<Item = TypeId> + 'a

Enumerate the types of the entity’s components

Convenient for dispatching component-specific logic for a single entity. For example, this can be combined with a HashMap<TypeId, Box<dyn Handler>> where Handler is some user-defined trait with methods for serialization, or to be called after spawning or before despawning to maintain secondary indices.

pub fn len(&self) -> usize

Number of components in this entity

pub fn is_empty(&self) -> bool

Shorthand for self.len() == 0

Trait Implementations

impl<'a> Clone for EntityRef<'a>

fn clone(&self) -> EntityRef<'a>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a> Copy for EntityRef<'a>

impl<'a> Send for EntityRef<'a>

impl<'a> Sync for EntityRef<'a>