Package	org.springextensions.actionscript.eventbus.process
Class	public class EventHandlerMetadataProcessor
Inheritance	EventHandlerMetadataProcessor AbstractEventBusMetadataProcessor AbstractSpringMetadataProcessor org.as3commons.metadata.process.impl.AbstractMetadataProcessor
Subclasses	EventHandlerMetadataDestroyer

IMetadataProcessor implementation that adds EventBus event handlers based on the annotations found in the object's class. These annotations mark a public method as an event handler of an event dispatched on the EventBus.

The metadata annotation takes the form of [EventHandler] in its simplest form. The name of the event will then be deducted from the method name. For instance, if you have an event called "saveUser", the handler is supposed to have the same name, or the same name with "Handler" attached to it. So "saveUser" and "saveUserHandler" are both valid handler names.

If the name of the event and the event handler are different, or for clarity reasons, you can specify the event name via the "name" argument on the metadata. For example [EventHandler(name="saveUser")] is a valid form. You can also leave out the key of the name argument and just type [EventHandler("saveUser")].

By default, an event handler function is expected to have a single argument of type Event (or any subclass). However if the event argument has additional properties, you can specify these properties directly as arguments of the handler function. For example if you have a UserEvent class with a property "user" of type User, the handler signature can look like this: function saveUser(user:User):void

If the custom event class has multiple properties of the same type, for example a "userA" and "userB" property both of type User, Spring ActionScript will not be able to figure out what properties correspond to the arguments of the handler function. In that case you need to specify the name of the properties in the metadata. e.g. [EventHandler(properties="userA, userB")]

If the event handler is for a specific event class, add the fully qualified classname to the metadata like this: [EventHandler(clazz="com.classes.events.MyEventClass")].

To determine if the event listener will be added using a weak reference, set the useWeakReference property like this: [EventHandler(clazz="com.classes.events.MyEventClass",useWeakReference="true")]

To subscribe the event listener for a specific topic or topics, use this extra argument: [EventHandler(clazz="com.classes.events.MyEventClass",topics="topic1,topic2")]

These metadata annotations can be stacked, so this is also valid:

	 [EventHandler(clazz="com.classes.events.MyEventClass1")]
	 [EventHandler(clazz="com.classes.events.MyEventClass2",topics="topic1")]
	 

Finally, to use the EventHandlerMetaDataPostProcessor in an application, add an object definition to the XML configuration like this:

	 <object id="eventhandlerProcessor" class="org.springextensions.actionscript.ioc.factory.config.EventHandlerMetaDataPostProcessor"/>
	 

This way the processor will be automatically registered with the application context.

See also

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