Struct ProjectionEngine 

pub struct ProjectionEngine { /* private fields */ }

Engine for managing multiple projections.

The ProjectionEngine:

• Registers fully composed Projection instances
• Routes events to interested projections
• Rebuilds projections from the event store
• Provides convenience registration via register_projector

Example

let event_store = Box::new(sqlite_event_store);
let mut engine = ProjectionEngine::new(event_store);

// Option 1: register a pre-composed projection
engine.register(Box::new(projection_unit));

// Option 2: convenience — register projector + store directly
engine.register_projector(Box::new(UserListProjector), store.clone(), "users_view");

// Process events
engine.process(&event).await?;

// Rebuild all projections from event store
engine.rebuild_all().await?;

Implementations

impl ProjectionEngine

pub fn new(event_store: Box<dyn EventStore>) -> Self

Create a new projection engine.

pub fn register(&mut self, projection: Box<dyn Projection>)

Register a fully composed projection.

pub fn register_projector( &mut self, projector: Box<dyn Projector>, store: Arc<dyn ReadModelStore>, table: impl Into<String>, )

Convenience: register a projector + store as a ProjectionUnit.

pub async fn process(&self, event: &Event) -> ProjectionResult<()>

Process a single event through all interested projections.

Routes the event to projections whose handles() includes the event type.

pub async fn process_batch(&self, events: Vec<Event>) -> ProjectionResult<()>

Process multiple events in sequence.

pub async fn rebuild_all(&self) -> ProjectionResult<()>

Rebuild all registered projections from the event store.

pub async fn rebuild_projection(&self, name: &str) -> ProjectionResult<()>

Rebuild a specific projection by name.

pub fn projection_count(&self) -> usize

Get number of registered projections.

pub fn projection_names(&self) -> Vec<String>

Get names of all registered projections.

pub fn all_handled_event_types(&self) -> Vec<String>

Union of every event type any registered projection handles. Used by ProjectionEngineHandler to declare its handles() set when subscribing to an EventBus.