Struct ChildQuery 

pub struct ChildQuery<'w, 's, T: QueryStream, C: EntityReference = Children> {
    pub query: Query<'w, 's, <<T as QueryStream>::Query as QueryData>::ReadOnly>,
    pub context: StaticSystemParam<'w, 's, <T as QueryStream>::Context>,
    pub children: Query<'w, 's, &'static C>,
}

SystemParam for querying QueryStreams on entities referenced by a component like Children.

query_relation implementation is disabled since the behavior is undefined.

Fields

query: Query<'w, 's, <<T as QueryStream>::Query as QueryData>::ReadOnly>

context: StaticSystemParam<'w, 's, <T as QueryStream>::Context>

children: Query<'w, 's, &'static C>

Trait Implementations

impl<T: QueryStream, C: EntityReference> StatStream for ChildQuery<'_, '_, T, C>

type Qualifier = <T as QueryStream>::Qualifier

fn stream_stat( &self, entity: Entity, qualifier: &QualifierQuery<Self::Qualifier>, stat_value: &mut StatValuePair, querier: Querier<'_, Self::Qualifier>, )

fn has_attribute(&self, entity: Entity, attribute: Attribute<'_>) -> bool

fn stream_relation( &self, other: &Self, entity: Entity, target: Entity, qualifier: &QualifierQuery<Self::Qualifier>, stat_value: &mut StatValuePair, querier: Querier<'_, Self::Qualifier>, )

impl<T: QueryStream, C: EntityReference> SystemParam for ChildQuery<'_, '_, T, C>

type State = FetchState<T, C>

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

type Item<'w, 's> = ChildQuery<'w, 's, T, C>

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) -> Self::State

Creates a new instance of this param’s State.

fn init_access( state: &Self::State, system_meta: &mut SystemMeta, component_access_set: &mut FilteredAccessSet, world: &mut World, )

Registers any World access used by this SystemParam

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<'w, 's>( state: &'s mut Self::State, _system_meta: &SystemMeta, _world: UnsafeWorldCell<'w>, ) -> Result<(), SystemParamValidationError>

Validates that the param can be acquired by the get_param.

unsafe fn get_param<'w, 's>( state: &'s mut Self::State, system_meta: &SystemMeta, world: UnsafeWorldCell<'w>, change_tick: Tick, ) -> Self::Item<'w, 's>

Creates a parameter to be passed into a SystemParamFunction.

impl<'w, 's, T: QueryStream, C: EntityReference> ReadOnlySystemParam for ChildQuery<'w, 's, T, C>

where Query<'w, 's, <<T as QueryStream>::Query as QueryData>::ReadOnly>: ReadOnlySystemParam, StaticSystemParam<'w, 's, <T as QueryStream>::Context>: ReadOnlySystemParam, Query<'w, 's, &'static C>: ReadOnlySystemParam,