com.lightbend.lagom.javadsl.persistence

Interface PersistentEntityRegistry

public interface PersistentEntityRegistry

At system startup all PersistentEntity classes must be registered here with register(java.lang.Class<? extends com.lightbend.lagom.javadsl.persistence.PersistentEntity<C, E, S>>).

Later, PersistentEntityRef can be retrieved with refFor(java.lang.Class<? extends com.lightbend.lagom.javadsl.persistence.PersistentEntity<C, ?, ?>>, java.lang.String). Commands are sent to a PersistentEntity using a PersistentEntityRef.

Method Summary

Modifier and Type	Method and Description
<Event extends AggregateEvent<Event>> akka.stream.javadsl.Source<akka.japi.Pair<Event,Offset>,akka.NotUsed>	eventStream(AggregateEventTag<Event> aggregateTag, Offset fromOffset) A stream of the persistent events that have the given aggregateTag, e.g.
<Event extends AggregateEvent<Event>> akka.stream.javadsl.Source<akka.japi.Pair<Event,UUID>,akka.NotUsed>	eventStream(AggregateEventTag<Event> aggregateTag, Optional<UUID> fromOffset) Deprecated. Use eventStream(AggregateEventTag, Offset) instead. Since 1.2.0.
<C> PersistentEntityRef<C>	refFor(Class<? extends PersistentEntity<C,?,?>> entityClass, String entityId) Retrieve a PersistentEntityRef for a given PersistentEntity class and identifier.
<C,E,S> void	register(Class<? extends PersistentEntity<C,E,S>> entityClass) At system startup all PersistentEntity classes must be registered with this method.

Method Detail

eventStream

<Event extends AggregateEvent<Event>> akka.stream.javadsl.Source<akka.japi.Pair<Event,Offset>,akka.NotUsed> eventStream(AggregateEventTag<Event> aggregateTag,
                                                                                                                        Offset fromOffset)

A stream of the persistent events that have the given aggregateTag, e.g. all persistent events of all Order entities.

The type of the offset is journal dependent, some journals use time-based UUID offsets, while others use sequence numbers. The passed in fromOffset must either be Offset.NONE, or an offset that has previously been produced by this journal.

The stream will begin with events starting ''after'' fromOffset. To resume an event stream, store the Offset corresponding to the most recently processed Event, and pass that back as the value for fromOffset to start the stream from events following that one.

Throws:

IllegalArgumentException - If the fromOffset type is not supported by this journal.

eventStream

<Event extends AggregateEvent<Event>> akka.stream.javadsl.Source<akka.japi.Pair<Event,UUID>,akka.NotUsed> eventStream(AggregateEventTag<Event> aggregateTag,
                                                                                                                      Optional<UUID> fromOffset)

Deprecated. Use eventStream(AggregateEventTag, Offset) instead. Since 1.2.0.

A stream of the persistent events that have the given aggregateTag, e.g. all persistent events of all Order entities.

This method will only work with journals that support UUID offsets. Journals that produce sequence offsets will fail during stream handling.

refFor

<C> PersistentEntityRef<C> refFor(Class<? extends PersistentEntity<C,?,?>> entityClass,
                                  String entityId)

Retrieve a PersistentEntityRef for a given PersistentEntity class and identifier. Commands are sent to a PersistentEntity using a PersistentEntityRef.

register

<C,E,S> void register(Class<? extends PersistentEntity<C,E,S>> entityClass)

At system startup all PersistentEntity classes must be registered with this method.