org.axonframework.eventsourcing.eventstore

Class AbstractEventStore

java.lang.Object

org.axonframework.eventhandling.AbstractEventBus

org.axonframework.eventsourcing.eventstore.AbstractEventStore

All Implemented Interfaces:

org.axonframework.eventhandling.DomainEventSequenceAware, org.axonframework.eventhandling.EventBus, EventStore, org.axonframework.messaging.MessageDispatchInterceptorSupport<org.axonframework.eventhandling.EventMessage<?>>, org.axonframework.messaging.StreamableMessageSource<org.axonframework.eventhandling.TrackedEventMessage<?>>, org.axonframework.messaging.SubscribableMessageSource<org.axonframework.eventhandling.EventMessage<?>>

Direct Known Subclasses:

EmbeddedEventStore, EmbeddedEventStore

public abstract class AbstractEventStore
extends org.axonframework.eventhandling.AbstractEventBus
implements EventStore

Abstract implementation of an EventStore that uses a EventStorageEngine to store and load events.

Since:

3.0

Author:

Rene de Waele

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AbstractEventStore.Builder Abstract Builder class to instantiate an AbstractEventStore.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractEventStore(AbstractEventStore.Builder builder) Instantiate an AbstractEventStore based on the fields contained in the AbstractEventStore.Builder.

Method Summary

Modifier and Type	Method and Description
org.axonframework.eventhandling.TrackingToken	createHeadToken()
org.axonframework.eventhandling.TrackingToken	createTailToken()
org.axonframework.eventhandling.TrackingToken	createTokenAt(Instant dateTime)
protected Optional<org.axonframework.eventhandling.DomainEventMessage<?>>	handleSnapshotReadingError(String aggregateIdentifier, Throwable e) Invoked when an error (Exception or LinkageError) occurs while attempting to read a snapshot event.
Optional<Long>	lastSequenceNumberFor(String aggregateIdentifier)
protected void	prepareCommit(List<? extends org.axonframework.eventhandling.EventMessage<?>> events)
DomainEventStream	readEvents(String aggregateIdentifier) Open an event stream containing all domain events belonging to the given aggregateIdentifier.
DomainEventStream	readEvents(String aggregateIdentifier, long firstSequenceNumber) Open an event stream containing all domain events belonging to the given aggregateIdentifier.
protected Stream<? extends org.axonframework.eventhandling.DomainEventMessage<?>>	stagedDomainEventMessages(String aggregateIdentifier) Returns a Stream of all DomainEventMessages that have been staged for publication by an Aggregate with given aggregateIdentifier.
protected EventStorageEngine	storageEngine() Returns the EventStorageEngine used by the event store.
void	storeSnapshot(org.axonframework.eventhandling.DomainEventMessage<?> snapshot) Stores the given (temporary) snapshot event.

Methods inherited from class org.axonframework.eventhandling.AbstractEventBus

afterCommit, commit, intercept, publish, queuedMessages, registerDispatchInterceptor, subscribe

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.axonframework.eventhandling.EventBus

publish, publish

Methods inherited from interface org.axonframework.messaging.SubscribableMessageSource

subscribe

Methods inherited from interface org.axonframework.messaging.MessageDispatchInterceptorSupport

registerDispatchInterceptor

Methods inherited from interface org.axonframework.messaging.StreamableMessageSource

createTokenSince, openStream

Constructor Detail

AbstractEventStore

protected AbstractEventStore(AbstractEventStore.Builder builder)

Instantiate an AbstractEventStore based on the fields contained in the AbstractEventStore.Builder.

Will assert that the EventStorageEngine is not null, and will throw an AxonConfigurationException if it is null.

Parameters:

builder - the AbstractEventStore.Builder used to instantiate a AbstractEventStore instance

Method Detail

prepareCommit

protected void prepareCommit(List<? extends org.axonframework.eventhandling.EventMessage<?>> events)

Overrides:

prepareCommit in class org.axonframework.eventhandling.AbstractEventBus

readEvents

public DomainEventStream readEvents(@Nonnull
                                    String aggregateIdentifier)

Open an event stream containing all domain events belonging to the given aggregateIdentifier.

The returned stream is finite, ending with the last known event of the aggregate. If the event store holds no events of the given aggregate an empty stream is returned.

This implementation returns a DomainEventStream starting with the last stored snapshot of the aggregate followed by subsequent domain events.

Specified by:

readEvents in interface EventStore

Parameters:

aggregateIdentifier - the identifier of the aggregate whose events to fetch

Returns:

a stream of all currently stored events of the aggregate

handleSnapshotReadingError

protected Optional<org.axonframework.eventhandling.DomainEventMessage<?>> handleSnapshotReadingError(String aggregateIdentifier,
                                                                                                     Throwable e)

Invoked when an error (Exception or LinkageError) occurs while attempting to read a snapshot event. This method can be overridden to change the default behavior, which is to log the exception (warn level) and ignore the snapshot.

Overriding implementations may choose to return normally, or raise an exception. Exceptions raised from this method are propagated to the caller of the readEvents(String) or readEvents(String, long) methods.

Returning an empty Optional will force the initialization of the aggregate to happen based on the entire event stream of that aggregate.

Parameters:

aggregateIdentifier - The identifier of the aggregate for which an snapshot failed to load

e - The exception or error that occurred while loading or deserializing the snapshot

Returns:

An optional DomainEventMessage to use as the snapshot for this aggregate

Throws:

RuntimeException - any runtimeException to fail loading the

stagedDomainEventMessages

protected Stream<? extends org.axonframework.eventhandling.DomainEventMessage<?>> stagedDomainEventMessages(String aggregateIdentifier)

Returns a Stream of all DomainEventMessages that have been staged for publication by an Aggregate with given aggregateIdentifier.

Parameters:

aggregateIdentifier - The identifier of the aggregate to get staged events for

Returns:

a Stream of DomainEventMessage of the identified aggregate

readEvents

public DomainEventStream readEvents(@Nonnull
                                    String aggregateIdentifier,
                                    long firstSequenceNumber)

Description copied from interface: EventStore

Open an event stream containing all domain events belonging to the given aggregateIdentifier.

The returned stream is finite, ending with the last known event of the aggregate. If the event store holds no events of the given aggregate an empty stream is returned.

The default implementation invokes EventStore.readEvents(String) and then filters out events with a sequence number smaller than firstSequenceNumber.

Specified by:

readEvents in interface EventStore

Parameters:

aggregateIdentifier - the identifier of the aggregate whose events to fetch

firstSequenceNumber - the expected sequence number of the first event in the returned stream

Returns:

a stream of all currently stored events of the aggregate

storeSnapshot

public void storeSnapshot(@Nonnull
                          org.axonframework.eventhandling.DomainEventMessage<?> snapshot)

Description copied from interface: EventStore

Stores the given (temporary) snapshot event. This snapshot replaces the segment of the event stream identified by the snapshot's Aggregate Identifier up to (and including) the event with the snapshot's sequence number.

These snapshots will only affect the DomainEventStream returned by the EventStore.readEvents(String) method. They do not change the events returned by StreamableMessageSource.openStream(TrackingToken) or those received by using SubscribableMessageSource.subscribe(java.util.function.Consumer).

Note that snapshots are considered a temporary replacement for Events, and are used as performance optimization. Event Store implementations may choose to ignore or delete snapshots.

Specified by:

storeSnapshot in interface EventStore

Parameters:

snapshot - The snapshot to replace part of the DomainEventStream.

storageEngine

protected EventStorageEngine storageEngine()

Returns the EventStorageEngine used by the event store.

Returns:

The event storage engine used by this event store

lastSequenceNumberFor

public Optional<Long> lastSequenceNumberFor(String aggregateIdentifier)

Specified by:

lastSequenceNumberFor in interface org.axonframework.eventhandling.DomainEventSequenceAware

Specified by:

lastSequenceNumberFor in interface EventStore

createTailToken

public org.axonframework.eventhandling.TrackingToken createTailToken()

Specified by:

createTailToken in interface org.axonframework.messaging.StreamableMessageSource<org.axonframework.eventhandling.TrackedEventMessage<?>>

createHeadToken

public org.axonframework.eventhandling.TrackingToken createHeadToken()

Specified by:

createHeadToken in interface org.axonframework.messaging.StreamableMessageSource<org.axonframework.eventhandling.TrackedEventMessage<?>>

createTokenAt

public org.axonframework.eventhandling.TrackingToken createTokenAt(Instant dateTime)

Specified by:

createTokenAt in interface org.axonframework.messaging.StreamableMessageSource<org.axonframework.eventhandling.TrackedEventMessage<?>>