org.axonframework.commandhandling.annotation
Class AnnotationCommandHandlerAdapter

java.lang.Object
  org.axonframework.util.AbstractHandlerInspector
      org.axonframework.util.AbstractHandlerInvoker
          org.axonframework.commandhandling.annotation.AnnotationCommandHandlerAdapter

All Implemented Interfaces:

CommandHandler<Object>, Subscribable

public class AnnotationCommandHandlerAdapter
extends AbstractHandlerInvoker
implements CommandHandler<Object>, Subscribable

Adapter that turns any @CommandHandler annotated bean into a CommandHandler implementation. Each annotated method is subscribed as a CommandHandler at the CommandBus for the command type specified by the parameter of that method.

Since:

0.5

Author:

Allard Buijze

See Also:

CommandHandler

Constructor Summary

AnnotationCommandHandlerAdapter(Object target, CommandBus commandBus)
Initialize the command handler adapter for the given target which is to be subscribed with the given commandBus.

Method Summary

Method	findCommandHandlerMethodFor(Object command) Returns the method that will be called to handle the given command.
Object	handle(Object command, UnitOfWork unitOfWork) Invokes the @CommandHandler annotated method that accepts the given command.
protected Object	onNoMethodFound(Class<?> parameterType) Indicates what needs to happen when no handler is found for a given parameter.
void	subscribe() Subscribe the command handlers to the command bus assigned during the initialization.
void	unsubscribe() Unsubscribe the command handlers from the command bus assigned during the initialization.

Methods inherited from class org.axonframework.util.AbstractHandlerInvoker

getTarget, invokeHandlerMethod, invokeHandlerMethod

Methods inherited from class org.axonframework.util.AbstractHandlerInspector

findHandlerMethod

Methods inherited from class java.lang.Object

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

Constructor Detail

AnnotationCommandHandlerAdapter

public AnnotationCommandHandlerAdapter(Object target,
                                       CommandBus commandBus)

Initialize the command handler adapter for the given target which is to be subscribed with the given commandBus.

Note that you need to call subscribe() to actually subscribe the command handlers to the command bus.

Parameters:

target - The object containing the @CommandHandler annotated methods

commandBus - The command bus to which the handlers must be subscribed

Method Detail

handle

public Object handle(Object command,
                     UnitOfWork unitOfWork)
              throws Throwable

Invokes the @CommandHandler annotated method that accepts the given command.

Specified by:

handle in interface CommandHandler<Object>

Parameters:

command - The command to handle

unitOfWork - The UnitOfWork the command is processed in

Returns:

the result of the command handling. Is Void.TYPE when the annotated handler has a void return value.

Throws:

NoHandlerForCommandException - when no handler is found for given command.

Throwable - any exception occurring while handling the command

subscribe

@PostConstruct
public void subscribe()

Subscribe the command handlers to the command bus assigned during the initialization. A subscription is made with the command bus for each accepted type of command.

Specified by:

subscribe in interface Subscribable

unsubscribe

@PreDestroy
public void unsubscribe()

Unsubscribe the command handlers from the command bus assigned during the initialization.

Specified by:

unsubscribe in interface Subscribable

onNoMethodFound

protected Object onNoMethodFound(Class<?> parameterType)

Description copied from class: AbstractHandlerInvoker

Indicates what needs to happen when no handler is found for a given parameter. The default behavior is to return Void.TYPE.

Overrides:

onNoMethodFound in class AbstractHandlerInvoker

Parameters:

parameterType - The type of parameter for which no handler could be found

Returns:

the value to return when no handler method is found. Defaults to Void.TYPE.

findCommandHandlerMethodFor

public Method findCommandHandlerMethodFor(Object command)

Returns the method that will be called to handle the given command. Returns null is no such method is found.

Parameters:

command - The command to find the handler method for

Returns:

the command handler method for the given command