org.axonframework.saga.annotation

Annotation Type SagaEventHandler

@Documented
@Retention(value=RUNTIME)
@Target(value=METHOD)
public @interface SagaEventHandler

Method-level annotation indicating that the annotated method i an event handler method for the saga instance.

Annotated methods must comply to a few simple rules:

• The method must accept 1 parameter: a subtype of EventMessage
• Return values are allowed, but are ignored
• Exceptions are highly discouraged, and are likely to be caught and ignored by the dispatchers

For each event, only a single annotated method will be invoked. This method is resolved in the following order

1. First, the event handler methods of the actual class (at runtime) are searched
2. If a method is found with a parameter that the domain event can be assigned to, it is marked as eligible
3. After a class has been evaluated (but before any super class), the most specific event handler method is called. That means that if an event handler for a class A and one for a class B are eligible, and B is a subclass of A, then the method with a parameter of type B will be chosen
4. If no method is found in the actual class, its super class is evaluated.
5. If still no method is found, the event listener ignores the event

Since:

0.7

Author:

Allard Buijze

See Also:

EventHandler

Required Element Summary

Required Elements

Modifier and Type	Required Element and Description
String	associationProperty The property in the event that will provide the value to find the Saga instance.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
String	keyName The key in the AssociationValue to use.
Class<?>	payloadType The type of event this method handles.

Element Detail

associationProperty

public abstract String associationProperty

The property in the event that will provide the value to find the Saga instance. Typically, this value is an aggregate identifier of an aggregate that a specific saga monitors.

keyName

public abstract String keyName

The key in the AssociationValue to use. Optional. Should only be configured if that property is different than the value given by associationProperty().

Default:

""

payloadType

public abstract Class<?> payloadType

The type of event this method handles. If specified, this handler will only be invoked for message that have a payload assignable to the given payload type. If unspecified, the first parameter of the method defines the type of supported event.

Default:

java.lang.Void.class