org.axonframework.eventhandling.saga.repository

Class LockingSagaRepository<T>

java.lang.Object

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

All Implemented Interfaces:

SagaRepository<T>

Direct Known Subclasses:

AnnotatedSagaRepository

public abstract class LockingSagaRepository<T>
extends Object
implements SagaRepository<T>

Abstract implementation of a saga repository that locks access to a saga while the saga is being operated on.

Author:

Rene de Waele

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	LockingSagaRepository(LockFactory lockFactory) Initializes a saga repository that locks access to a saga while the saga is being operated on.

Method Summary

Modifier and Type	Method and Description
Saga<T>	createInstance(String sagaIdentifier, Supplier<T> factoryMethod) Creates a new Saga instance.
protected abstract Saga<T>	doCreateInstance(String sagaIdentifier, Supplier<T> factoryMethod) Creates a new Saga instance.
protected abstract Saga<T>	doLoad(String sagaIdentifier) Loads a known Saga instance by its unique identifier.
Saga<T>	load(String sagaIdentifier) Loads a known Saga instance by its unique identifier.

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.saga.SagaRepository

find

Constructor Detail

LockingSagaRepository

protected LockingSagaRepository(LockFactory lockFactory)

Initializes a saga repository that locks access to a saga while the saga is being operated on.

Parameters:

lockFactory - the factory of locks used by this repository

Method Detail

load

public Saga<T> load(String sagaIdentifier)

Loads a known Saga instance by its unique identifier. 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.

This implementation locks access to sagas with the given sagaIdentifier and releases the lock in the clean-up phase of the current UnitOfWork.

Specified by:

load in interface SagaRepository<T>

Parameters:

sagaIdentifier - The unique identifier of the Saga to load

Returns:

The Saga instance, or null if no such saga exists

createInstance

public Saga<T> createInstance(String sagaIdentifier,
                              Supplier<T> factoryMethod)

Creates a new Saga instance. The returned Saga will delegate event handling to the instance supplied by the given factoryMethod.

This implementation locks access to sagas with the given sagaIdentifier and releases the lock in the clean-up phase of the current UnitOfWork.

Specified by:

createInstance in interface SagaRepository<T>

Parameters:

sagaIdentifier - the identifier to use for the new saga instance

factoryMethod - Used to create a new Saga delegate

Returns:

a new Saga instance wrapping an instance of type T

doLoad

protected abstract Saga<T> doLoad(String sagaIdentifier)

Loads a known Saga instance by its unique identifier. 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.

Parameters:

sagaIdentifier - The unique identifier of the Saga to load

Returns:

The Saga instance, or null if no such saga exists

doCreateInstance

protected abstract Saga<T> doCreateInstance(String sagaIdentifier,
                                            Supplier<T> factoryMethod)

Creates a new Saga instance. The returned Saga will delegate event handling to the instance supplied by the given factoryMethod.

Parameters:

sagaIdentifier - the identifier to use for the new saga instance

factoryMethod - Used to create a new Saga delegate

Returns:

a new Saga instance wrapping an instance of type T