org.axonframework.commandhandling.disruptor

Class DisruptorUnitOfWork

java.lang.Object

org.axonframework.commandhandling.disruptor.DisruptorUnitOfWork

All Implemented Interfaces:

EventRegistrationCallback, UnitOfWork

public class DisruptorUnitOfWork
extends Object
implements UnitOfWork, EventRegistrationCallback

Specialized UnitOfWork instance for the DisruptorCommandBus. It expects the executing command to target a single aggregate instance.

Since:

2.0

Author:

Allard Buijze

Constructor Summary

Constructors

Constructor and Description
DisruptorUnitOfWork(boolean transactional) Creates a new Unit of Work for use in the DisruptorCommandBus.

Method Summary

Methods

Modifier and Type	Method and Description
void	commit() Commits the UnitOfWork.
EventSourcedAggregateRoot	getAggregate() Returns the identifier of the aggregate modified in this UnitOfWork.
String	getAggregateType() Returns the type identifier of the aggregate handled in this unit of work.
List<EventMessage>	getEventsToPublish() Returns the events that need to be published as part of this Unit of Work.
DomainEventStream	getEventsToStore() Returns the events that need to be stored as part of this Unit of Work.
boolean	isStarted() Indicates whether this UnitOfWork is started.
boolean	isTransactional() Indicates whether this UnitOfWork is bound to a transaction.
void	onAfterCommit() Invokes this UnitOfWork's on-after-commit cycle.
void	onCleanup() Invokes this UnitOfWork's on-cleanup cycle.
void	onPrepareCommit() Invokes this UnitOfWork's on-prepare-commit cycle.
void	onPrepareTransactionCommit(Object transaction) Invokes this UnitOfWork's on-prepare-transaction-commit cycle.
<T> DomainEventMessage<T>	onRegisteredEvent(DomainEventMessage<T> event) Invoked when an Aggregate registers an Event for publication.
void	onRollback(Throwable cause) Invokes this UnitOfWork's on-rollback cycle.
void	publishEvent(EventMessage event, EventBus eventBus) Request to publish the given event on the given eventBus.
<T extends AggregateRoot> T	registerAggregate(T aggregateRoot, EventBus eventBus, SaveAggregateCallback<T> saveAggregateCallback) Register an aggregate with this UnitOfWork.
void	registerListener(UnitOfWorkListener listener) Register a listener that listens to state changes in this UnitOfWork.
void	rollback() Clear the UnitOfWork of any buffered changes.
void	rollback(Throwable cause) Clear the UnitOfWork of any buffered changes.
void	setAggregateType(String aggregateType) Sets the type identifier of the aggregate handled in this unit of work
void	start() Starts the current unit of work, preparing it for aggregate registration.

Methods inherited from class java.lang.Object

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

Constructor Detail

DisruptorUnitOfWork

public DisruptorUnitOfWork(boolean transactional)

Creates a new Unit of Work for use in the DisruptorCommandBus.

Parameters:

transactional - Whether this Unit of Work is bound to a transaction

Method Detail

commit

public void commit()

Description copied from interface: UnitOfWork

Commits the UnitOfWork. All registered aggregates that have not been registered as stored are saved in their respective repositories, buffered events are sent to their respective event bus, and all registered UnitOfWorkListeners are notified.

After the commit (successful or not), the UnitOfWork is unregistered from the CurrentUnitOfWork and has cleaned up all resources it occupied. This effectively means that a rollback is done if Unit Of Work failed to commit.

Specified by:

commit in interface UnitOfWork

onPrepareCommit

public void onPrepareCommit()

Invokes this UnitOfWork's on-prepare-commit cycle. Typically, this is run after the actual aggregates have been committed, but before any of the changes are made public.

onPrepareTransactionCommit

public void onPrepareTransactionCommit(Object transaction)

Invokes this UnitOfWork's on-prepare-transaction-commit cycle.

Parameters:

transaction - The object representing the transaction to about to be committed

onAfterCommit

public void onAfterCommit()

Invokes this UnitOfWork's on-after-commit cycle. Typically, this is run after all the events have been stored and published.

onCleanup

public void onCleanup()

Invokes this UnitOfWork's on-cleanup cycle. Typically, this is run after all the events have been stored and published and the after-commit cycle has been executed.

onRollback

public void onRollback(Throwable cause)

Invokes this UnitOfWork's on-rollback cycle. Typically, this is run after all the events have been stored and published and the after-commit cycle has been executed.

Parameters:

cause - The cause of the rollback

rollback

public void rollback()

Description copied from interface: UnitOfWork

Clear the UnitOfWork of any buffered changes. All buffered events and registered aggregates are discarded and registered UnitOfWorkListeners are notified.

If the rollback is a result of an exception, consider using UnitOfWork.rollback(Throwable) instead.

Specified by:

rollback in interface UnitOfWork

rollback

public void rollback(Throwable cause)

Description copied from interface: UnitOfWork

Clear the UnitOfWork of any buffered changes. All buffered events and registered aggregates are discarded and registered UnitOfWorkListeners are notified.

Specified by:

rollback in interface UnitOfWork

Parameters:

cause - The cause of the rollback. May be null.

start

public void start()

Description copied from interface: UnitOfWork

Starts the current unit of work, preparing it for aggregate registration. The UnitOfWork instance is registered with the CurrentUnitOfWork.

Specified by:

start in interface UnitOfWork

isStarted

public boolean isStarted()

Description copied from interface: UnitOfWork

Indicates whether this UnitOfWork is started. It is started when the UnitOfWork.start() method has been called, and if the UnitOfWork has not been committed or rolled back.

Specified by:

isStarted in interface UnitOfWork

Returns:

true if this UnitOfWork is started, false otherwise.

isTransactional

public boolean isTransactional()

Description copied from interface: UnitOfWork

Indicates whether this UnitOfWork is bound to a transaction.

Specified by:

isTransactional in interface UnitOfWork

Returns:

true if this unit of work is bound to a transaction, otherwise false

registerListener

public void registerListener(UnitOfWorkListener listener)

Description copied from interface: UnitOfWork

Register a listener that listens to state changes in this UnitOfWork. This typically allows components to clean up resources, such as locks, when a UnitOfWork is committed or rolled back. If a UnitOfWork is partially committed, only the listeners bound to one of the committed aggregates is notified.

Specified by:

registerListener in interface UnitOfWork

Parameters:

listener - The listener to notify when the UnitOfWork's state changes.

registerAggregate

public <T extends AggregateRoot> T registerAggregate(T aggregateRoot,
                                            EventBus eventBus,
                                            SaveAggregateCallback<T> saveAggregateCallback)

Description copied from interface: UnitOfWork

Register an aggregate with this UnitOfWork. These aggregates will be saved (at the latest) when the UnitOfWork is committed. This method returns the instance of the aggregate root that should be used as part of the processing in this Unit Of Work.

If an aggregate of the same type and with the same identifier has already been registered, one of two things may happen, depending on the actual implementation:

• the instance that has already been registered is returned. In which case the given saveAggregateCallback is ignored.
• an IllegalStateException is thrown to indicate an illegal attempt to register a duplicate

.

Specified by:

registerAggregate in interface UnitOfWork

Type Parameters:

T - the type of aggregate to register

Parameters:

aggregateRoot - The aggregate root to register in the UnitOfWork

eventBus - The event bus on which Events generated by this aggregate must be published

saveAggregateCallback - The callback that is invoked when the UnitOfWork wants to store the registered aggregate

Returns:

The actual aggregate instance to use

publishEvent

public void publishEvent(EventMessage event,
                EventBus eventBus)

Description copied from interface: UnitOfWork

Request to publish the given event on the given eventBus. The UnitOfWork may either publish immediately, or buffer the events until the UnitOfWork is committed.

Specified by:

publishEvent in interface UnitOfWork

Parameters:

event - The event to be published on the event bus

eventBus - The event bus on which to publish the event

getEventsToStore

public DomainEventStream getEventsToStore()

Returns the events that need to be stored as part of this Unit of Work.

Returns:

the events that need to be stored as part of this Unit of Work

getEventsToPublish

public List<EventMessage> getEventsToPublish()

Returns the events that need to be published as part of this Unit of Work.

Returns:

the events that need to be published as part of this Unit of Work

getAggregate

public EventSourcedAggregateRoot getAggregate()

Returns the identifier of the aggregate modified in this UnitOfWork.

Returns:

the identifier of the aggregate modified in this UnitOfWork

onRegisteredEvent

public <T> DomainEventMessage<T> onRegisteredEvent(DomainEventMessage<T> event)

Description copied from interface: EventRegistrationCallback

Invoked when an Aggregate registers an Event for publication. The simplest implementation will simply return the given event.

Specified by:

onRegisteredEvent in interface EventRegistrationCallback

Type Parameters:

T - The type of payload

Parameters:

event - The event registered for publication

Returns:

the message to actually publish. May not be null.

getAggregateType

public String getAggregateType()

Returns the type identifier of the aggregate handled in this unit of work.

Returns:

the type identifier of the aggregate handled in this unit of work

setAggregateType

public void setAggregateType(String aggregateType)

Sets the type identifier of the aggregate handled in this unit of work

Parameters:

aggregateType - the type identifier of the aggregate handled in this unit of work