org.axonframework.commandhandling

Class AggregateAnnotationCommandHandler<T>

java.lang.Object

org.axonframework.commandhandling.AggregateAnnotationCommandHandler<T>

Type Parameters:

T - the type of aggregate this handler handles commands for

All Implemented Interfaces:

SupportedCommandNamesAware, MessageHandler<CommandMessage<?>>

public class AggregateAnnotationCommandHandler<T>
extends Object
implements MessageHandler<CommandMessage<?>>, SupportedCommandNamesAware

Command handler that handles commands based on CommandHandler annotations on an aggregate. Those annotations may appear on methods, in which case a specific aggregate instance needs to be targeted by the command, or on the constructor. The latter will create a new Aggregate instance, which is then stored in the repository.

Since:

1.2

Author:

Allard Buijze

Constructor Summary

Constructors

Constructor and Description
AggregateAnnotationCommandHandler(Class<T> aggregateType, Repository<T> repository) Initializes an AnnotationCommandHandler based on the annotations on given aggregateType, using the given repository to add and load aggregate instances.
AggregateAnnotationCommandHandler(Class<T> aggregateType, Repository<T> repository, CommandTargetResolver commandTargetResolver) Initializes an AnnotationCommandHandler based on the annotations on given aggregateType, using the given repository to add and load aggregate instances and the default ParameterResolverFactory.
AggregateAnnotationCommandHandler(Class<T> aggregateType, Repository<T> repository, CommandTargetResolver commandTargetResolver, ParameterResolverFactory parameterResolverFactory) Initializes an AnnotationCommandHandler based on the annotations on given aggregateType, using the given repository to add and load aggregate instances and the given parameterResolverFactory.
AggregateAnnotationCommandHandler(Repository<T> repository, CommandTargetResolver commandTargetResolver, AggregateModel<T> aggregateModel) Initializes an AnnotationCommandHandler based on the annotations on given aggregateType, using the given repository to add and load aggregate instances and the given parameterResolverFactory.

Method Summary

Modifier and Type	Method and Description
Object	handle(CommandMessage<?> commandMessage) Handles the given message.
protected Object	resolveReturnValue(CommandMessage<?> command, Aggregate<T> createdAggregate) Resolves the value to return when the given command has created the given aggregate.
Registration	subscribe(CommandBus commandBus) Subscribe this command handler to the given commandBus.
Set<String>	supportedCommandNames() Returns the set of command names this component supports.

Methods inherited from class java.lang.Object

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

Constructor Detail

AggregateAnnotationCommandHandler

public AggregateAnnotationCommandHandler(Class<T> aggregateType,
                                         Repository<T> repository)

Initializes an AnnotationCommandHandler based on the annotations on given aggregateType, using the given repository to add and load aggregate instances.

Parameters:

aggregateType - The type of aggregate

repository - The repository providing access to aggregate instances

AggregateAnnotationCommandHandler

public AggregateAnnotationCommandHandler(Class<T> aggregateType,
                                         Repository<T> repository,
                                         CommandTargetResolver commandTargetResolver)

Initializes an AnnotationCommandHandler based on the annotations on given aggregateType, using the given repository to add and load aggregate instances and the default ParameterResolverFactory.

Parameters:

aggregateType - The type of aggregate

repository - The repository providing access to aggregate instances

commandTargetResolver - The target resolution strategy

AggregateAnnotationCommandHandler

public AggregateAnnotationCommandHandler(Class<T> aggregateType,
                                         Repository<T> repository,
                                         CommandTargetResolver commandTargetResolver,
                                         ParameterResolverFactory parameterResolverFactory)

Initializes an AnnotationCommandHandler based on the annotations on given aggregateType, using the given repository to add and load aggregate instances and the given parameterResolverFactory.

Parameters:

aggregateType - The type of aggregate

repository - The repository providing access to aggregate instances

commandTargetResolver - The target resolution strategy

parameterResolverFactory - The strategy for resolving parameter values for handler methods

AggregateAnnotationCommandHandler

public AggregateAnnotationCommandHandler(Repository<T> repository,
                                         CommandTargetResolver commandTargetResolver,
                                         AggregateModel<T> aggregateModel)

Initializes an AnnotationCommandHandler based on the annotations on given aggregateType, using the given repository to add and load aggregate instances and the given parameterResolverFactory.

Parameters:

repository - The repository providing access to aggregate instances

commandTargetResolver - The target resolution strategy

aggregateModel - The description of the command handling model

Method Detail

subscribe

public Registration subscribe(CommandBus commandBus)

Subscribe this command handler to the given commandBus. The command handler will be subscribed for each of the supported commands.

Parameters:

commandBus - The command bus instance to subscribe to

Returns:

A handle that can be used to unsubscribe

handle

public Object handle(CommandMessage<?> commandMessage)
              throws Exception

Description copied from interface: MessageHandler

Handles the given message.

Specified by:

handle in interface MessageHandler<CommandMessage<?>>

Parameters:

commandMessage - The message to be processed.

Returns:

The result of the message processing.

Throws:

Exception - any exception that occurs during message handling

resolveReturnValue

protected Object resolveReturnValue(CommandMessage<?> command,
                                    Aggregate<T> createdAggregate)

Resolves the value to return when the given command has created the given aggregate. This implementation returns the identifier of the created aggregate.

This method may be overridden to change the return value of this Command Handler

Parameters:

command - The command being executed

createdAggregate - The aggregate that has been created as a result of the command

Returns:

The value to report as result of the command

supportedCommandNames

public Set<String> supportedCommandNames()

Description copied from interface: SupportedCommandNamesAware

Returns the set of command names this component supports.

Specified by:

supportedCommandNames in interface SupportedCommandNamesAware

Returns:

the set of supported command names