Package org.axonframework.messaging.commandhandling.annotation

Class AnnotatedCommandHandlingComponent<T>

java.lang.Object
org.axonframework.messaging.commandhandling.annotation.AnnotatedCommandHandlingComponent<T>
Type Parameters:
T - The target type of this command handling component.
All Implemented Interfaces:
DescribableComponent, CommandHandler, CommandHandlingComponent, MessageHandler
public class AnnotatedCommandHandlingComponent<T> extends Object implements CommandHandlingComponent
Adapter that turns classes with CommandHandler annotated methods into a CommandHandlingComponent.

Each annotated method is subscribed as a CommandHandler at the CommandHandlingComponent with the command name specified by the parameter of that method.

Since:
0.5.0
Author:
Allard Buijze

  • Constructor Details

    • AnnotatedCommandHandlingComponent

      public AnnotatedCommandHandlingComponent(@Nonnull T annotatedCommandHandler, @Nonnull ParameterResolverFactory parameterResolverFactory, @Nonnull HandlerDefinition handlerDefinition, @Nonnull MessageTypeResolver messageTypeResolver, @Nonnull MessageConverter converter)
      Wraps the given annotatedCommandHandler, allowing it to be subscribed to a CommandBus as a CommandHandlingComponent.
      Parameters:
      annotatedCommandHandler - The object containing the CommandHandler annotated methods.
      parameterResolverFactory - The parameter resolver factory to resolve handler parameters with.
      handlerDefinition - The handler definition used to create concrete handlers.
      messageTypeResolver - The MessageTypeResolver resolving the names for CommandMessages.
      converter - The converter to use for converting the payload of the command to the type expected by the handling method.

  • Method Details

    • handle

      @Nonnull public MessageStream.Single<CommandResultMessage> handle(@Nonnull CommandMessage command, @Nonnull ProcessingContext processingContext)
      Description copied from interface: CommandHandler
      Handles the given command within the given context.

      The result message in the returned stream may be null. Only a single or empty result message should ever be expected.

      Specified by:
      handle in interface CommandHandler
      Parameters:
      command - The command to handle.
      processingContext - The context to the given command is handled in.
      Returns:
      A MessagesStream.Single of a CommandResultMessage.

    • supportedCommands

      public Set<QualifiedName> supportedCommands()
      Description copied from interface: CommandHandlingComponent
      All supported commands, referenced through a QualifiedName.
      Specified by:
      supportedCommands in interface CommandHandlingComponent
      Returns:
      All supported commands, referenced through a QualifiedName.

    • describeTo

      public void describeTo(@Nonnull ComponentDescriptor descriptor)
      Description copied from interface: DescribableComponent
      Describe the properties of this DescribableComponent with the given descriptor.

      Components should call the appropriate describeProperty methods on the descriptor to register their properties. The descriptor is responsible for determining how these properties are formatted and structured in the final output.

      Best Practices: As a general rule, all relevant fields of a DescribableComponent implementation should be described in this method. However, developers have discretion to include only the fields that make sense in the context. Not every field may be meaningful for description purposes, especially internal implementation details. Furthermore, components might want to expose different information based on their current state. The final decision on what properties to include lies with the person implementing the describeTo method, who should focus on providing information that is useful for understanding the component's configuration and state.

      Example implementation: 

       public void describeTo(ComponentDescriptor descriptor) {
     descriptor.describeProperty("name", this.name);
     descriptor.describeProperty("enabled", this.enabled);
     descriptor.describeProperty("configuration", this.configuration); // A nested component
     descriptor.describeProperty("handlers", this.eventHandlers);      // A collection
 }
      Specified by:
      describeTo in interface DescribableComponent
      Parameters:
      descriptor - The component descriptor to describe this DescribableComponentn its properties in.