Struct Components 

pub struct Components { /* private fields */ }

Stores metadata associated with each kind of Component in a given World.

Implementations

impl Components

pub fn len(&self) -> usize

Returns the number of components registered or queued with this instance.

pub fn is_empty(&self) -> bool

Returns true if there are no components registered or queued with this instance. Otherwise, this returns false.

pub fn num_queued(&self) -> usize

Returns the number of components registered with this instance.

pub fn any_queued(&self) -> bool

Returns true if there are any components registered with this instance. Otherwise, this returns false.

pub fn num_queued_mut(&mut self) -> usize

A faster version of Self::num_queued.

pub fn any_queued_mut(&mut self) -> bool

A faster version of Self::any_queued.

pub fn num_registered(&self) -> usize

Returns the number of components registered with this instance.

pub fn any_registered(&self) -> bool

Returns true if there are any components registered with this instance. Otherwise, this returns false.

pub fn get_info(&self, id: ComponentId) -> Option<&ComponentInfo>

Gets the metadata associated with the given component, if it is registered. This will return None if the id is not registered or is queued.

This will return an incorrect result if id did not come from the same world as self. It may return None or a garbage value.

pub fn get_descriptor<'a>( &'a self, id: ComponentId, ) -> Option<Cow<'a, ComponentDescriptor>>

Gets the ComponentDescriptor of the component with this ComponentId if it is present. This will return None only if the id is neither registered nor queued to be registered.

Currently, the Cow will be Cow::Owned if and only if the component is queued. It will be Cow::Borrowed otherwise.

This will return an incorrect result if id did not come from the same world as self. It may return None or a garbage value.

pub fn get_name<'a>(&'a self, id: ComponentId) -> Option<DebugName>

Gets the name of the component with this ComponentId if it is present. This will return None only if the id is neither registered nor queued to be registered.

This will return an incorrect result if id did not come from the same world as self. It may return None or a garbage value.

pub unsafe fn get_info_unchecked(&self, id: ComponentId) -> &ComponentInfo

Gets the metadata associated with the given component.

Safety

id must be a valid and fully registered ComponentId.

pub fn is_id_valid(&self, id: ComponentId) -> bool

Returns true if the ComponentId is fully registered and valid. Ids may be invalid if they are still queued to be registered. Those ids are still correct, but they are not usable in every context yet.

pub fn get_valid_id(&self, type_id: TypeId) -> Option<ComponentId>

Type-erased equivalent of Components::valid_component_id().

pub fn valid_component_id<T>(&self) -> Option<ComponentId>

where T: Component,

Returns the ComponentId of the given Component type T if it is fully registered. If you want to include queued registration, see Components::component_id().

use bevy_ecs::prelude::*;

let mut world = World::new();

#[derive(Component)]
struct ComponentA;

let component_a_id = world.register_component::<ComponentA>();

assert_eq!(component_a_id, world.components().valid_component_id::<ComponentA>().unwrap())

See also

• Components::get_valid_id()
• Components::valid_resource_id()
• World::component_id()

pub fn get_valid_resource_id(&self, type_id: TypeId) -> Option<ComponentId>

Type-erased equivalent of Components::valid_resource_id().

pub fn valid_resource_id<T>(&self) -> Option<ComponentId>

where T: Resource,

Returns the ComponentId of the given Resource type T if it is fully registered. If you want to include queued registration, see Components::resource_id().

use bevy_ecs::prelude::*;

let mut world = World::new();

#[derive(Resource, Default)]
struct ResourceA;

let resource_a_id = world.init_resource::<ResourceA>();

assert_eq!(resource_a_id, world.components().valid_resource_id::<ResourceA>().unwrap())

See also

• Components::valid_component_id()
• Components::get_resource_id()

pub fn get_id(&self, type_id: TypeId) -> Option<ComponentId>

Type-erased equivalent of Components::component_id().

pub fn component_id<T>(&self) -> Option<ComponentId>

where T: Component,

Returns the ComponentId of the given Component type T.

The returned ComponentId is specific to the Components instance it was retrieved from and should not be used with another Components instance.

Returns None if the Component type has not yet been initialized using ComponentsRegistrator::register_component() or ComponentsQueuedRegistrator::queue_register_component().

use bevy_ecs::prelude::*;

let mut world = World::new();

#[derive(Component)]
struct ComponentA;

let component_a_id = world.register_component::<ComponentA>();

assert_eq!(component_a_id, world.components().component_id::<ComponentA>().unwrap())

See also

• ComponentIdFor
• Components::get_id()
• Components::resource_id()
• World::component_id()

pub fn get_resource_id(&self, type_id: TypeId) -> Option<ComponentId>

Type-erased equivalent of Components::resource_id().

pub fn resource_id<T>(&self) -> Option<ComponentId>

where T: Resource,

Returns the ComponentId of the given Resource type T.

The returned ComponentId is specific to the Components instance it was retrieved from and should not be used with another Components instance.

Returns None if the Resource type has not yet been initialized using ComponentsRegistrator::register_resource() or ComponentsQueuedRegistrator::queue_register_resource().

use bevy_ecs::prelude::*;

let mut world = World::new();

#[derive(Resource, Default)]
struct ResourceA;

let resource_a_id = world.init_resource::<ResourceA>();

assert_eq!(resource_a_id, world.components().resource_id::<ResourceA>().unwrap())

See also

• Components::component_id()
• Components::get_resource_id()

pub fn iter_registered(&self) -> impl Iterator<Item = &ComponentInfo>

Gets an iterator over all components fully registered with this instance.

Trait Implementations

impl Debug for Components

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for Components

fn default() -> Components

Returns the “default value” for a type.

impl<'a> SystemParam for &'a Components

type State = ()

Used to store data which persists across invocations of a system.

type Item<'w, 's> = &'w Components

The item type returned when constructing this system param. The value of this associated type should be Self, instantiated with new lifetimes.

fn init_state(_world: &mut World) -> <&'a Components as SystemParam>::State

Creates a new instance of this param’s State.

fn init_access( _state: &<&'a Components as SystemParam>::State, _system_meta: &mut SystemMeta, _component_access_set: &mut FilteredAccessSet, _world: &mut World, )

Registers any World access used by this SystemParam

unsafe fn get_param<'w, 's>( _state: &'s mut <&'a Components as SystemParam>::State, _system_meta: &SystemMeta, world: UnsafeWorldCell<'w>, _change_tick: Tick, ) -> <&'a Components as SystemParam>::Item<'w, 's>

Creates a parameter to be passed into a SystemParamFunction.

fn apply(state: &mut Self::State, system_meta: &SystemMeta, world: &mut World)

Applies any deferred mutations stored in this SystemParam’s state. This is used to apply Commands during ApplyDeferred.

fn queue( state: &mut Self::State, system_meta: &SystemMeta, world: DeferredWorld<'_>, )

Queues any deferred mutations to be applied at the next ApplyDeferred.

unsafe fn validate_param( state: &mut Self::State, system_meta: &SystemMeta, world: UnsafeWorldCell<'_>, ) -> Result<(), SystemParamValidationError>

Validates that the param can be acquired by the get_param.

impl<'a> ReadOnlySystemParam for &'a Components