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Akka.NETIEventAdapter Interface

An IEventAdapter is both a IWriteEventAdapter and a IReadEventAdapter. Facility to convert from and to specialised data models, as may be required by specialized persistence Journals.

Typical use cases include (but are not limited to):

- adding metadata, a.k.a. "tagging" - by wrapping objects into tagged counterparts

- manually converting to the Journals storage format, such as JSON, BSON or any specialised binary format

- adapting incoming events in any way before persisting them by the journal

Namespace:  Akka.Persistence.Journal
Assembly:  Akka.Persistence (in Akka.Persistence.dll) Version: (
public interface IEventAdapter : IWriteEventAdapter, 

The IEventAdapter type exposes the following members.

Public methodFromJournal

Convert an event from its journal model to the application's domain model.

One event may be adapter into multiple(or none) events which should be delivered to the PersistentActor. Use the specialised Single(Object) method to emit exactly one event, or Empty in case the adapter is not handling this event. Multiple IEventAdapter instances are applied in order as defined in configuration and their emitted event seqs are concatenated and delivered in order to the PersistentActor.

(Inherited from IReadEventAdapter.)
Public methodManifest
Return the manifest (type hint) that will be provided in the [!:FromJournal] method. Use empty string if not needed.
(Inherited from IWriteEventAdapter.)
Public methodToJournal

Convert domain event to journal event type.

Some journal may require a specific type to be returned to them, for example if a primary key has to be associated with each event then a journal may require adapters to return "EventWithPrimaryKey(event, key)".

The ToJournal(Object) adaptation must be an 1-to-1 transformation. It is not allowed to drop incoming events during the `toJournal` adaptation.

(Inherited from IWriteEventAdapter.)
See Also