Interface SnapshotStore

All Superinterfaces:
Namespaced<SnapshotStore>
All Known Implementing Classes:
DefaultSnapshotStore, NoOpSnapshotStore
public interface SnapshotStore extends Namespaced<SnapshotStore>
Interface for managing snapshots of aggregates in an event-sourced system.

Snapshots are serialized representations of an aggregate's state at a certain point in time (i.e., after a certain sequence number). They allow the system to avoid replaying the entire event history for aggregates with large event logs.

This interface defines methods for storing, loading, and deleting such snapshots. Snapshots are typically used in combination with AggregateRepository and EventStore to optimize aggregate loading.

Usage of this interface is optional—if no snapshot is found, the aggregate is reconstructed from its full event history.

  • Method Details

    • forNamespace

      default SnapshotStore forNamespace(String namespace)
      Returns this snapshot store scoped to the requested namespace.

      Implementations that do not use namespace-aware backing storage may keep returning the same instance. The default implementation switches both its document and event stores to the requested namespace.

      Specified by:
      forNamespace in interface Namespaced<SnapshotStore>
      Parameters:
      namespace - the namespace to which the returned store is scoped
      Returns:
      the snapshot store associated with the specified namespace

    • storeSnapshot

      <T> CompletableFuture<Void> storeSnapshot(Entity<T> snapshot)
      Stores a new snapshot for the given aggregate entity.

      The snapshot typically contains the latest known state and metadata such as the aggregate ID and sequence number. Storing a snapshot will overwrite any existing snapshot for the same aggregate ID.

      Type Parameters:
      T - The aggregate root type.
      Parameters:
      snapshot - The aggregate entity to be stored as a snapshot.
      Returns:
      A CompletableFuture indicating whether the operation completed successfully.

    • getSnapshot

      <T> Optional<Entity<T>> getSnapshot(Object aggregateId)
      Retrieves the most recent snapshot for a given aggregate ID, if available.
      Type Parameters:
      T - The expected type of the aggregate.
      Parameters:
      aggregateId - The ID of the aggregate for which to retrieve a snapshot.
      Returns:
      An Optional containing the aggregate snapshot if present, otherwise empty.

    • getSnapshotBefore

      <T> Optional<Entity<T>> getSnapshotBefore(Object aggregateId, long sequenceNumberExclusive)
      Retrieves the most recent snapshot with a sequence number strictly lower than the given value.
      Type Parameters:
      T - The expected aggregate type.
      Parameters:
      aggregateId - The aggregate identifier.
      sequenceNumberExclusive - Upper bound (exclusive) for the snapshot sequence number.
      Returns:
      An Optional containing the matching snapshot if present.

    • deleteSnapshot

      CompletableFuture<Void> deleteSnapshot(Object aggregateId)
      Deletes the snapshot for the specified aggregate ID.
      Parameters:
      aggregateId - The ID of the aggregate whose snapshot should be deleted.
      Returns:
      A CompletableFuture indicating completion of the deletion operation.