Continuum Event Sourcing

Event sourcing persistence strategy for Continuum. Provides event store abstractions, JSON serialization, projection system, and the event-sourcing-specific session that extends the Unit of Work session engine.

Installation

dependencies:
  continuum: latest
  continuum_event_sourcing: latest
  continuum_store_memory: latest  # or continuum_store_hive / continuum_store_sembast

dev_dependencies:
  build_runner: ^2.4.0
  continuum_generator: latest

Key Concepts

EventSourcingStore

The configuration root for event-sourced persistence. Aggregates are reconstructed by replaying stored events.

import 'package:continuum_event_sourcing/continuum_event_sourcing.dart';
import 'package:continuum_store_memory/continuum_store_memory.dart';
import 'continuum.g.dart';

final store = EventSourcingStore(
  eventStore: InMemoryEventStore(),
  targets: $aggregateList,
);

final session = store.openSession();
await session.applyAsync<User>(userId, UserRegistered(...));
await session.saveChangesAsync();

EventStore & AtomicEventStore

EventStore is the persistence interface for reading and writing event streams. AtomicEventStore adds optimistic concurrency via expected-version checks. Store implementations (continuum_store_memory, continuum_store_hive, continuum_store_sembast) implement these interfaces.

Serialization

Events are serialized to JSON via JsonEventSerializer. Implement toJson() / fromJson() on your events and register them through @OperationFor(type: YourTarget, key: '...').

Projections

Maintain read models automatically updated when events occur. Supports single-stream and multi-stream projections with inline (strongly consistent) or async (eventually consistent) execution.

Architecture

This package sits at Layer 2 of the Continuum architecture. It depends on continuum (core types) and continuum_uow (session engine).

License

MIT