org.axonframework.eventsourcing

Class AbstractSnapshotter

java.lang.Object

org.axonframework.eventsourcing.AbstractSnapshotter

All Implemented Interfaces:

Snapshotter

Direct Known Subclasses:

AggregateSnapshotter

public abstract class AbstractSnapshotter
extends Object
implements Snapshotter

Abstract implementation of the Snapshotter that uses a task executor to creates snapshots. Actual snapshot creation logic should be provided by a subclass.

Since:

0.6

Author:

Allard Buijze

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractSnapshotter(EventStore eventStore) Initializes the Snapshotter to append snapshots in the given eventStore.
protected	AbstractSnapshotter(EventStore eventStore, Executor executor, TransactionManager transactionManager) Initializes the Snapshotter to append snapshots in the given eventStore.
protected	AbstractSnapshotter(EventStore eventStore, TransactionManager transactionManager) Initializes the Snapshotter to append snapshots in the given eventStore.

Method Summary

Modifier and Type	Method and Description
protected abstract DomainEventMessage	createSnapshot(Class<?> aggregateType, String aggregateIdentifier, DomainEventStream eventStream) Creates a snapshot event for an aggregate of which passed events are available in the given eventStream.
protected Runnable	createSnapshotterTask(Class<?> aggregateType, String aggregateIdentifier) Creates an instance of a task that contains the actual snapshot creation logic.
protected EventStore	getEventStore() Returns the event store this snapshotter uses to load domain events and store snapshot events.
protected Executor	getExecutor() Returns the executor that executes snapshot taking tasks.
void	scheduleSnapshot(Class<?> aggregateType, String aggregateIdentifier) Schedules snapshot taking for an aggregate with given aggregateIdentifier.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractSnapshotter

protected AbstractSnapshotter(EventStore eventStore)

Initializes the Snapshotter to append snapshots in the given eventStore. This snapshotter will create the snapshots in the process that triggers them, and save them into the Event Store without any transaction.

Parameters:

eventStore - the EventStore instance to store snapshots in

AbstractSnapshotter

protected AbstractSnapshotter(EventStore eventStore,
                              TransactionManager transactionManager)

Initializes the Snapshotter to append snapshots in the given eventStore. This snapshotter will create the snapshots in the process that triggers them, and save them into the Event Store in a transaction managed by the given transactionManager.

Parameters:

eventStore - the EventStore instance to store snapshots in

transactionManager - The transaction manager to create the surrounding transaction with

AbstractSnapshotter

protected AbstractSnapshotter(EventStore eventStore,
                              Executor executor,
                              TransactionManager transactionManager)

Initializes the Snapshotter to append snapshots in the given eventStore. This snapshotter will create the snapshots in the process provided by the given executor, and save them into the Event Store in a transaction managed by the given transactionManager.

Parameters:

eventStore - The EventStore instance to store snapshots in

executor - The executor that handles the actual snapshot creation process

transactionManager - The transaction manager to create the surrounding transaction with

Method Detail

scheduleSnapshot

public void scheduleSnapshot(Class<?> aggregateType,
                             String aggregateIdentifier)

Description copied from interface: Snapshotter

Schedules snapshot taking for an aggregate with given aggregateIdentifier. The implementation may choose to process this call synchronously (i.e. in the caller's thread), asynchronously, or ignore the call altogether.

Specified by:

scheduleSnapshot in interface Snapshotter

Parameters:

aggregateType - the type of the aggregate to take the snapshot for

aggregateIdentifier - The identifier of the aggregate to take the snapshot for

createSnapshotterTask

protected Runnable createSnapshotterTask(Class<?> aggregateType,
                                         String aggregateIdentifier)

Creates an instance of a task that contains the actual snapshot creation logic.

Parameters:

aggregateType - The type of the aggregate to create a snapshot for

aggregateIdentifier - The identifier of the aggregate to create a snapshot for

Returns:

the task containing snapshot creation logic

createSnapshot

protected abstract DomainEventMessage createSnapshot(Class<?> aggregateType,
                                                     String aggregateIdentifier,
                                                     DomainEventStream eventStream)

Creates a snapshot event for an aggregate of which passed events are available in the given eventStream. May return null to indicate a snapshot event is not necessary or appropriate for the given event stream.

Parameters:

aggregateType - The aggregate's type identifier

aggregateIdentifier - The identifier of the aggregate to create a snapshot for

eventStream - The event stream containing the aggregate's past events

Returns:

the snapshot event for the given events, or null if none should be stored.

getEventStore

protected EventStore getEventStore()

Returns the event store this snapshotter uses to load domain events and store snapshot events.

Returns:

the event store this snapshotter uses to load domain events and store snapshot events.

getExecutor

protected Executor getExecutor()

Returns the executor that executes snapshot taking tasks.

Returns:

the executor that executes snapshot taking tasks.