org.axonframework.queryhandling.annotation

Class AnnotationQueryHandlerAdapter<T>

java.lang.Object

org.axonframework.queryhandling.annotation.AnnotationQueryHandlerAdapter<T>

All Implemented Interfaces:

MessageHandler<QueryMessage<?,?>>, QueryHandlerAdapter

public class AnnotationQueryHandlerAdapter<T>
extends Object
implements QueryHandlerAdapter, MessageHandler<QueryMessage<?,?>>

Adapter that turns any @QueryHandler annotated bean into a MessageHandler implementation. Each annotated method is subscribed as a QueryHandler at the QueryBus for the query type specified by the parameter/return type of that method.

Since:

3.1

Author:

Marc Gathier

Constructor Summary

Constructors

Constructor and Description
AnnotationQueryHandlerAdapter(T target) Initializes the adapter, forwarding call to the given target.
AnnotationQueryHandlerAdapter(T target, ParameterResolverFactory parameterResolverFactory) Initializes the adapter, forwarding call to the given target, resolving parameters using the given parameterResolverFactory.
AnnotationQueryHandlerAdapter(T target, ParameterResolverFactory parameterResolverFactory, HandlerDefinition handlerDefinition) Initializes the adapter, forwarding call to the given target, resolving parameters using the given parameterResolverFactory and creating handlers using handlerDefinition.

Method Summary

Modifier and Type	Method and Description
boolean	canHandle(QueryMessage<?,?> message) Indicates whether this handler can handle the given message
Object	handle(QueryMessage<?,?> message) Handles the given message.
Registration	subscribe(QueryBus queryBus) Subscribes the query handlers of this QueryHandlerAdapter to the given QueryBus.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.axonframework.messaging.MessageHandler

canHandleType, getTargetType

Constructor Detail

AnnotationQueryHandlerAdapter

public AnnotationQueryHandlerAdapter(T target)

Initializes the adapter, forwarding call to the given target.

Parameters:

target - the instance with QueryHandler annotated methods

AnnotationQueryHandlerAdapter

public AnnotationQueryHandlerAdapter(T target,
                                     ParameterResolverFactory parameterResolverFactory)

Initializes the adapter, forwarding call to the given target, resolving parameters using the given parameterResolverFactory.

Parameters:

target - the instance with QueryHandler annotated methods

parameterResolverFactory - the parameter resolver factory to resolve handler parameters with

AnnotationQueryHandlerAdapter

public AnnotationQueryHandlerAdapter(T target,
                                     ParameterResolverFactory parameterResolverFactory,
                                     HandlerDefinition handlerDefinition)

Initializes the adapter, forwarding call to the given target, resolving parameters using the given parameterResolverFactory and creating handlers using handlerDefinition.

Parameters:

target - the instance with QueryHandler annotated methods

parameterResolverFactory - the parameter resolver factory to resolve handler parameters with

handlerDefinition - the handler definition used to create concrete handlers

Method Detail

subscribe

public Registration subscribe(@Nonnull
                              QueryBus queryBus)

Description copied from interface: QueryHandlerAdapter

Subscribes the query handlers of this QueryHandlerAdapter to the given QueryBus.

Specified by:

subscribe in interface QueryHandlerAdapter

Parameters:

queryBus - the query bus to subscribe

Returns:

a Registration to unsubscribe this QueryHandlerAdapter

handle

public Object handle(QueryMessage<?,?> message)
              throws Exception

Description copied from interface: MessageHandler

Handles the given message.

Specified by:

handle in interface MessageHandler<QueryMessage<?,?>>

Parameters:

message - The message to be processed.

Returns:

The result of the message processing.

Throws:

Exception - any exception that occurs during message handling

canHandle

public boolean canHandle(QueryMessage<?,?> message)

Description copied from interface: MessageHandler

Indicates whether this handler can handle the given message

Specified by:

canHandle in interface MessageHandler<QueryMessage<?,?>>

Parameters:

message - The message to verify

Returns:

true if this handler can handle the message, otherwise false