Query

If you need to query the stored events you can use Persistence Query to stream them from the journal (Scala and Java supported).

Get read journal in Scala:

import akka.actor.ActorSystem
import akka.persistence.query.PersistenceQuery
import com.fgrutsch.akka.persistence.mapdb.query.scaladsl.MapDbReadJournal

val actorSystem: ActorSystem        = ???
val readJournal: MapDbReadJournal   = PersistenceQuery(actorSystem)
                                       .readJournalFor[MapDbReadJournal](MapDbReadJournal.Identifier)

Get read journal in Java:

import akka.actor.ActorSystem
import akka.persistence.query.PersistenceQuery
import com.fgrutsch.akka.persistence.mapdb.query.javadsl.MapDbReadJournal

final ActorSystem actorSystem         = ???
final MapDbReadJournal readJournal    = PersistenceQuery.get(actorSystem)
                                        .getReadJournalFor[MapDbReadJournal](MapDbReadJournal.Identifier)

All query operations are supported:

• Get persistenceIds (current)
• Get persistenceIds (live)
• Get events by persistenceId (current)
• Get events by persistenceId (live)
• Get events by tag (current)
• Get events by tag (live)

Configuration

The internal behavior of the read journal queries can be changed (e.g. refresh interval). For instructions please check the Configuration page on how to change that.

Event Adapters

When reading events from the journal the MapDbReadJournal applies configured events adapters thay you may have configured in the write plugin (under the mapdb-journal configuration key).