CassandraReadJournal

Value Members

1. final def !=(arg0: Any): Boolean

   

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2. final def ##(): Int

   

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3. final def ==(arg0: Any): Boolean

   

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4. final def asInstanceOf[T0]: T0

   

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5. def clone(): AnyRef

   

   Attributes

   protected[java.lang]

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   Annotations

   @throws( ... )

6. def config: CassandraJournalConfig

   

   Definition Classes

   CassandraReadJournal → CassandraStatements

7. def createTagScanningTable: String

   

   Definition Classes

   CassandraStatements

8. def createTagsProgressTable: String

   

   Definition Classes

   CassandraStatements

9. def currentEventsByPersistenceId(persistenceId: String, fromSequenceNr: Long, toSequenceNr: Long): Source[EventEnvelope, NotUsed]

   

   Same type of query as eventsByPersistenceId but the event stream is completed immediately when it reaches the end of the "result set".

   Same type of query as eventsByPersistenceId but the event stream is completed immediately when it reaches the end of the "result set". Events that are stored after the query is completed are not included in the event stream.

   Definition Classes

   CassandraReadJournal → CurrentEventsByPersistenceIdQuery

10. def currentEventsByTag(tag: String, offset: Offset): Source[EventEnvelope, NotUsed]

    

    Same type of query as eventsByTag but the event stream is completed immediately when it reaches the end of the "result set".

    Same type of query as eventsByTag but the event stream is completed immediately when it reaches the end of the "result set". Events that are stored after the query is completed are not included in the event stream.

    Use NoOffset when you want all events from the beginning of time. To acquire an offset from a long unix timestamp to use with this query, you can use timeBasedUUIDFrom.

    Definition Classes

    CassandraReadJournal → CurrentEventsByTagQuery

11. def currentPersistenceIds(): Source[String, NotUsed]

    

    Same type of query as allPersistenceIds but the event stream is completed immediately when it reaches the end of the "result set".

    Same type of query as allPersistenceIds but the event stream is completed immediately when it reaches the end of the "result set". Events that are stored after the query is completed are not included in the event stream.

    Definition Classes

    CassandraReadJournal → CurrentPersistenceIdsQuery

12. final def eq(arg0: AnyRef): Boolean

    

    Definition Classes

    AnyRef

13. def equals(arg0: Any): Boolean

    

    Definition Classes

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14. def eventsByPersistenceId(persistenceId: String, fromSequenceNr: Long, toSequenceNr: Long): Source[EventEnvelope, NotUsed]

    

    eventsByPersistenceId is used to retrieve a stream of events for a particular persistenceId.

    eventsByPersistenceId is used to retrieve a stream of events for a particular persistenceId.

    In addition to the offset the EventEnvelope also provides persistenceId and sequenceNr for each event. The sequenceNr is the sequence number for the persistent actor with the persistenceId that persisted the event. The persistenceId + sequenceNr is an unique identifier for the event.

    sequenceNr and offset are always the same for an event and they define ordering for events emitted by this query. Causality is guaranteed (sequenceNrs of events for a particular persistenceId are always ordered in a sequence monotonically increasing by one). Multiple executions of the same bounded stream are guaranteed to emit exactly the same stream of events.

    fromSequenceNr and toSequenceNr can be specified to limit the set of returned events. The fromSequenceNr and toSequenceNr are inclusive.

    Deleted events are also deleted from the event stream.

    The stream is not completed when it reaches the end of the currently stored events, but it continues to push new events when new events are persisted. Corresponding query that is completed when it reaches the end of the currently stored events is provided by currentEventsByPersistenceId.

    Definition Classes

    CassandraReadJournal → EventsByPersistenceIdQuery

15. def eventsByTag(tag: String, offset: Offset): Source[EventEnvelope, NotUsed]

    

    eventsByTag is used for retrieving events that were marked with a given tag, e.g.

    eventsByTag is used for retrieving events that were marked with a given tag, e.g. all events of an Aggregate Root type.

    To tag events you create an akka.persistence.journal.EventAdapter that wraps the events in a akka.persistence.journal.Tagged with the given tags. The tags must be defined in the tags section of the cassandra-journal configuration.

    You can use NoOffset to retrieve all events with a given tag or retrieve a subset of all events by specifying a TimeBasedUUID offset.

    The offset of each event is provided in the streamed envelopes returned, which makes it possible to resume the stream at a later point from a given offset.

    For querying events that happened after a long unix timestamp you can use timeBasedUUIDFrom to create the offset to use with this method.

    In addition to the offset the envelope also provides persistenceId and sequenceNr for each event. The sequenceNr is the sequence number for the persistent actor with the persistenceId that persisted the event. The persistenceId + sequenceNr is an unique identifier for the event.

    The returned event stream is ordered by the offset (timestamp), which corresponds to the same order as the write journal stored the events, with inaccuracy due to clock skew between different nodes. The same stream elements (in same order) are returned for multiple executions of the query on a best effort basis. The query is using a batched writes to a separate table so is eventually consistent. This means that different queries may see different events for the latest events, but eventually the result will be ordered by timestamp (Cassandra timeuuid column).

    However a strong guarantee is provided that events for a given persistenceId will be delivered in order, the eventual consistency is only for ordering of events from different persistenceIds.

    The stream is not completed when it reaches the end of the currently stored events, but it continues to push new events when new events are persisted. Corresponding query that is completed when it reaches the end of the currently stored events is provided by currentEventsByTag.

    The stream is completed with failure if there is a failure in executing the query in the backend journal.

    Definition Classes

    CassandraReadJournal → EventsByTagQuery

16. def finalize(): Unit

    

    Attributes

    protected[java.lang]

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    @throws( classOf[java.lang.Throwable] )

17. val firstOffset: UUID

    

    Use this as the UUID offset in eventsByTag queries when you want all events from the beginning of time.

18. final def getClass(): Class[_]

    

    Definition Classes

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19. def hashCode(): Int

    

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20. def initialize(): Future[Done]

    

    Initialize connection to Cassandra and prepared statements.

    Initialize connection to Cassandra and prepared statements. It is not required to do this and it will happen lazily otherwise. It is also not required to wait until this Future is complete to start using the read journal.

21. final def isInstanceOf[T0]: Boolean

    

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22. final def ne(arg0: AnyRef): Boolean

    

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23. final def notify(): Unit

    

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24. final def notifyAll(): Unit

    

    Definition Classes

    AnyRef

25. def offsetUuid(timestamp: Long): UUID

    

    Create a time based UUID that can be used as offset in eventsByTag queries.

    Create a time based UUID that can be used as offset in eventsByTag queries. The timestamp is a unix timestamp (as returned by System#currentTimeMillis.

26. def persistenceIds(): Source[String, NotUsed]

    

    allPersistenceIds is used to retrieve a stream of persistenceIds.

    allPersistenceIds is used to retrieve a stream of persistenceIds.

    The stream emits persistenceId strings.

    The stream guarantees that a persistenceId is only emitted once and there are no duplicates. Order is not defined. Multiple executions of the same stream (even bounded) may emit different sequence of persistenceIds.

    The stream is not completed when it reaches the end of the currently known persistenceIds, but it continues to push new persistenceIds when new events are persisted. Corresponding query that is completed when it reaches the end of the currently known persistenceIds is provided by currentPersistenceIds.

    Note the query is inefficient, especially for large numbers of persistenceIds, because of limitation of current internal implementation providing no information supporting ordering/offset queries. The query uses Cassandra's select distinct capabilities. More importantly the live query has to repeatedly execute the query each refresh-interval, because order is not defined and new persistenceIds may appear anywhere in the query results.

    Definition Classes

    CassandraReadJournal → PersistenceIdsQuery

27. val session: CassandraSession

    

    Data Access Object for arbitrary queries or updates.

28. final def synchronized[T0](arg0: ⇒ T0): T0

    

    Definition Classes

    AnyRef

29. def tableName: String

    

    Attributes

    protected

    Definition Classes

    CassandraStatements

30. def timeBasedUUIDFrom(timestamp: Long): Offset

    

    Create a time based UUID that can be used as offset in eventsByTag queries.

    Create a time based UUID that can be used as offset in eventsByTag queries. The timestamp is a unix timestamp (as returned by System#currentTimeMillis.

31. def timestampFrom(offset: TimeBasedUUID): Long

    

    Convert a TimeBasedUUID to a unix timestamp (as returned by System#currentTimeMillis.

32. def toString(): String

    

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33. final def wait(): Unit

    

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34. final def wait(arg0: Long, arg1: Int): Unit

    

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35. final def wait(arg0: Long): Unit

    

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