org.axonframework.eventhandling.saga.repository

Class CachingSagaStore<T>

java.lang.Object

org.axonframework.eventhandling.saga.repository.CachingSagaStore<T>

All Implemented Interfaces:

SagaStore<T>

public class CachingSagaStore<T>
extends Object
implements SagaStore<T>

Saga Repository implementation that adds caching behavior to the repository it wraps. Both associations and sagas are cached, making loading them faster. Commits and adds are always delegated to the wrapped repository. Loads are only delegated if the cache does not contain the necessary entries.

Updating associations involves a read and a write, which are performed atomically. Therefore, it is unsafe to add or remove specific associations outside of this instance. Obviously, clearing and evictions are safe.

Since:

2.0

Author:

Allard Buijze

Nested Class Summary

Nested classes/interfaces inherited from interface org.axonframework.eventhandling.saga.repository.SagaStore

SagaStore.Entry<T>

Constructor Summary

Constructors

Constructor and Description
CachingSagaStore(SagaStore<T> delegate, Cache associationsCache, Cache sagaCache) Initializes an instance delegating to the given delegate, storing associations in the given associationsCache and Saga instances in the given sagaCache.

Method Summary

Modifier and Type	Method and Description
protected void	addCachedAssociations(Iterable<AssociationValue> associationValues, String sagaIdentifier, Class<?> sagaType) Registers the associations of a saga with given sagaIdentifier and given sagaType with the associations cache.
void	deleteSaga(Class<? extends T> sagaType, String sagaIdentifier, Set<AssociationValue> associationValues) Deletes a Saga with given sagaType and sagaIdentifier and all its associations.
Set<String>	findSagas(Class<? extends T> sagaType, AssociationValue associationValue) Returns identifiers of saga instances of the given sagaType that have been associated with the given associationValue.
void	insertSaga(Class<? extends T> sagaType, String sagaIdentifier, T saga, TrackingToken token, Set<AssociationValue> associationValues) Adds a new Saga and its initial association values to the store.
<S extends T> SagaStore.Entry<S>	loadSaga(Class<S> sagaType, String sagaIdentifier) Loads a known saga SagaStore.Entry instance with given sagaType and unique sagaIdentifier.
void	updateSaga(Class<? extends T> sagaType, String sagaIdentifier, T saga, TrackingToken token, AssociationValues associationValues) Updates a given Saga after its state was modified.

Methods inherited from class java.lang.Object

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

Constructor Detail

CachingSagaStore

public CachingSagaStore(SagaStore<T> delegate,
                        Cache associationsCache,
                        Cache sagaCache)

Initializes an instance delegating to the given delegate, storing associations in the given associationsCache and Saga instances in the given sagaCache.

Parameters:

delegate - The repository instance providing access to (persisted) entries

associationsCache - The cache to store association information is

sagaCache - The cache to store Saga instances in

Method Detail

findSagas

public Set<String> findSagas(Class<? extends T> sagaType,
                             AssociationValue associationValue)

Description copied from interface: SagaStore

Returns identifiers of saga instances of the given sagaType that have been associated with the given associationValue.

Specified by:

findSagas in interface SagaStore<T>

Parameters:

sagaType - The type of the returned sagas

associationValue - The value that the returned sagas must be associated with

Returns:

A set of identifiers of sagas having the correct type and association value

loadSaga

public <S extends T> SagaStore.Entry<S> loadSaga(Class<S> sagaType,
                                                 String sagaIdentifier)

Description copied from interface: SagaStore

Loads a known saga SagaStore.Entry instance with given sagaType and unique sagaIdentifier.

Due to the concurrent nature of Sagas, it is not unlikely for a Saga to have ceased to exist after it has been found based on associations. Therefore, a repository should return null in case a Saga doesn't exists, as opposed to throwing an exception.

Specified by:

loadSaga in interface SagaStore<T>

Parameters:

sagaType - The type of the returned saga entry

sagaIdentifier - The unique identifier of the returned saga entry

Returns:

The saga entry, or null if no such saga exists

insertSaga

public void insertSaga(Class<? extends T> sagaType,
                       String sagaIdentifier,
                       T saga,
                       TrackingToken token,
                       Set<AssociationValue> associationValues)

Description copied from interface: SagaStore

Adds a new Saga and its initial association values to the store. The tracking token of the event last handled by the Saga (usually the event that started the Saga) is also passed as a parameter. Note that the given token may be null if the Saga is not tracking the event store.

Specified by:

insertSaga in interface SagaStore<T>

Parameters:

sagaType - The type of the Saga

sagaIdentifier - The identifier of the Saga

saga - The Saga instance

token - The tracking token of the event last handled by the Saga. May be null.

associationValues - The initial association values of the Saga

deleteSaga

public void deleteSaga(Class<? extends T> sagaType,
                       String sagaIdentifier,
                       Set<AssociationValue> associationValues)

Description copied from interface: SagaStore

Deletes a Saga with given sagaType and sagaIdentifier and all its associations. For convenience all known association values are passed along as well, which has the advantage that the saga store is not required to keep an index of association value to saga identifier.

Specified by:

deleteSaga in interface SagaStore<T>

Parameters:

sagaType - The type of saga to delete

sagaIdentifier - The identifier of the saga to delete

associationValues - The known associations of the saga

addCachedAssociations

protected void addCachedAssociations(Iterable<AssociationValue> associationValues,
                                     String sagaIdentifier,
                                     Class<?> sagaType)

Registers the associations of a saga with given sagaIdentifier and given sagaType with the associations cache.

Parameters:

associationValues - the association values of the saga

sagaIdentifier - the identifier of the saga

sagaType - the type of the saga

updateSaga

public void updateSaga(Class<? extends T> sagaType,
                       String sagaIdentifier,
                       T saga,
                       TrackingToken token,
                       AssociationValues associationValues)

Description copied from interface: SagaStore

Updates a given Saga after its state was modified. The tracking token of the event last handled by the Saga is also passed as a parameter. Note that the given token may be null if the Saga is not tracking the event store.

Specified by:

updateSaga in interface SagaStore<T>

Parameters:

sagaType - The type of the Saga

sagaIdentifier - The identifier of the Saga

saga - The Saga instance

token - The tracking token of the event last handled by the Saga. May be null.

associationValues - The initial association values of the Saga