Package org.axonframework.eventhandling

Class AnnotationEventHandlerAdapter

java.lang.Object

org.axonframework.eventhandling.AnnotationEventHandlerAdapter

All Implemented Interfaces:

EventMessageHandler, MessageHandler<EventMessage<?>>

public class AnnotationEventHandlerAdapter
extends Object
implements EventMessageHandler

Adapter that turns any bean with EventHandler annotated methods into an EventMessageHandler.

Since:

0.1

Author:

Allard Buijze

See Also:

• EventMessageHandler

Constructor Summary

Constructors

Constructor	Description
AnnotationEventHandlerAdapter(Object annotatedEventListener)	Wraps the given annotatedEventListener, allowing it to be subscribed to an Event Bus.
AnnotationEventHandlerAdapter(Object annotatedEventListener, ParameterResolverFactory parameterResolverFactory)	Wraps the given annotatedEventListener, allowing it to be subscribed to an Event Bus.
AnnotationEventHandlerAdapter(Object annotatedEventListener, ParameterResolverFactory parameterResolverFactory, HandlerDefinition handlerDefinition)	Wraps the given annotatedEventListener, allowing it to be subscribed to an Event Bus.

Method Summary

Modifier and Type	Method	Description
boolean	canHandle(EventMessage<?> event)	Indicates whether this handler can handle the given message
boolean	canHandleType(Class<?> payloadType)	Indicates whether this handler can handle messages of given type
Class<?>	getTargetType()	Returns the instance type that this handler delegates to.
Object	handle(EventMessage<?> event)	Process the given event.
void	prepareReset()	Performs any activities that are required to reset the state managed by handlers assigned to this handler.
<R> void	prepareReset(R resetContext)	Performs any activities that are required to reset the state managed by handlers assigned to this handler.
boolean	supportsReset()	Indicates whether the handlers managed by this invoker support a reset.

Methods inherited from class java.lang.Object

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

Constructor Details

AnnotationEventHandlerAdapter

public AnnotationEventHandlerAdapter(Object annotatedEventListener)

Wraps the given annotatedEventListener, allowing it to be subscribed to an Event Bus.

Parameters:

annotatedEventListener - the annotated event listener

AnnotationEventHandlerAdapter

public AnnotationEventHandlerAdapter(Object annotatedEventListener,
 ParameterResolverFactory parameterResolverFactory)

Wraps the given annotatedEventListener, allowing it to be subscribed to an Event Bus. The given parameterResolverFactory is used to resolve parameter values for handler methods.

Parameters:

annotatedEventListener - the annotated event listener

parameterResolverFactory - the strategy for resolving handler method parameter values

AnnotationEventHandlerAdapter

public AnnotationEventHandlerAdapter(Object annotatedEventListener,
 ParameterResolverFactory parameterResolverFactory,
 HandlerDefinition handlerDefinition)

Wraps the given annotatedEventListener, allowing it to be subscribed to an Event Bus. The given parameterResolverFactory is used to resolve parameter values for handler methods. Handler definition is used to create concrete handlers.

Parameters:

annotatedEventListener - the annotated event listener

parameterResolverFactory - the strategy for resolving handler method parameter values

handlerDefinition - the handler definition used to create concrete handlers

Method Details

handle

public Object handle(EventMessage<?> event)
              throws Exception

Description copied from interface: EventMessageHandler

Process the given event. The implementation may decide to process or skip the given event. It is highly unrecommended to throw any exception during the event handling process.

Specified by:

handle in interface EventMessageHandler

Specified by:

handle in interface MessageHandler<EventMessage<?>>

Parameters:

event - the event to handle

Returns:

the result of the event handler invocation. Is generally ignored

Throws:

Exception - when an exception is raised during event handling

canHandle

public boolean canHandle(EventMessage<?> event)

Description copied from interface: MessageHandler

Indicates whether this handler can handle the given message

Specified by:

canHandle in interface MessageHandler<EventMessage<?>>

Parameters:

event - The message to verify

Returns:

true if this handler can handle the message, otherwise false

canHandleType

public boolean canHandleType(Class<?> payloadType)

Description copied from interface: MessageHandler

Indicates whether this handler can handle messages of given type

Specified by:

canHandleType in interface MessageHandler<EventMessage<?>>

Parameters:

payloadType - The payloadType to verify

Returns:

true if this handler can handle the payloadType, otherwise false

getTargetType

public Class<?> getTargetType()

Description copied from interface: MessageHandler

Returns the instance type that this handler delegates to.

Specified by:

getTargetType in interface MessageHandler<EventMessage<?>>

Returns:

Returns the instance type that this handler delegates to

prepareReset

public void prepareReset()

Description copied from interface: EventMessageHandler

Performs any activities that are required to reset the state managed by handlers assigned to this handler.

Specified by:

prepareReset in interface EventMessageHandler

prepareReset

public <R> void prepareReset(R resetContext)

Description copied from interface: EventMessageHandler

Performs any activities that are required to reset the state managed by handlers assigned to this handler.

Specified by:

prepareReset in interface EventMessageHandler

Type Parameters:

R - the type of the provided resetContext

Parameters:

resetContext - a R used to support the reset operation

supportsReset

public boolean supportsReset()

Indicates whether the handlers managed by this invoker support a reset.

Specified by:

supportsReset in interface EventMessageHandler

Returns:

true if a reset is supported, otherwise false

Implementation Note:

This implementation will consider any class that has a single handler that accepts a replay, to support reset. If no handlers explicitly indicate whether replay is supported, the method returns true.