Trait ProjectionFilters 

pub trait ProjectionFilters: Sized {
    type Id;
    type InstanceId;
    type Metadata;

    // Required methods
    fn init(instance_id: &Self::InstanceId) -> Self;
    fn filters<S>(instance_id: &Self::InstanceId) -> Filters<S, Self>
       where S: EventStore<Id = Self::Id, Metadata = Self::Metadata>;
}

Base trait for types that subscribe to events.

The filters() method returns both the event filters AND the handlers needed to process those events. It is generic over the store type S, allowing the same projection to work with any store that shares the same Id and Metadata types.

filters() must be pure and deterministic: given the same instance_id, it must always return the same filter set.

init() constructs a fresh instance from the instance identifier. This replaces the Default constraint, allowing instance-aware projections to capture their identity at construction time.

Required Associated Types

type Id

Aggregate identifier type this subscriber is compatible with.

type InstanceId

Instance identifier for this subscriber.

For singleton subscribers use ().

type Metadata

Metadata type expected by this subscriber’s handlers.

Required Methods

fn init(instance_id: &Self::InstanceId) -> Self

Construct a fresh instance from the instance identifier.

For singleton projections (InstanceId = ()), this typically delegates to Self::default(). For instance projections, this captures the instance identifier at construction time.

fn filters<S>(instance_id: &Self::InstanceId) -> Filters<S, Self>

where S: EventStore<Id = Self::Id, Metadata = Self::Metadata>,

Build the filter set and handler map for this subscriber.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors