Package net.engio.mbassy.listener

Annotation Type Handler

  • @Retention(RUNTIME)
@Inherited
@Target({METHOD,ANNOTATION_TYPE})
public @interface Handler
    Mark any method of any class(=listener) as a message handler and configure the handler using different properties.

    • Optional Element Summary

      Optional Elements 
      Modifier and Type Optional Element Description
      java.lang.String condition
      Defines a filter condition as Expression Language.
      Invoke delivery
      Define the mode in which a message is delivered to each listener.
      boolean enabled
      Enable or disable the handler.
      Filter[] filters
      Add any numbers of filters to the handler.
      java.lang.Class<? extends HandlerInvocation> invocation
      Each handler call is implemented as an invocation object that implements the invocation mechanism.
      int priority
      Handlers are ordered by priority and handlers with higher priority are processed before those with lower priority, i.e.
      boolean rejectSubtypes
      Define whether or not the handler accepts sub types of the message type it declares in its signature.

    • Element Detail

      • filters

        Filter[] filters
        Add any numbers of filters to the handler. All filters are evaluated before the handler is actually invoked, which is only if all the filters accept the message.
        Default:
        {}

      • condition

        java.lang.String condition
        Defines a filter condition as Expression Language. This can be used to filter the events based on attributes of the event object. Note that the expression must resolve to either true to allow the event or false to block it from delivery to the handler. The message itself is available as "msg" variable.
        Returns:
        the condition in EL syntax.
        Default:
        ""

      • delivery

        Invoke delivery
        Define the mode in which a message is delivered to each listener. Listeners can be notified sequentially or concurrently.
        Default:
        net.engio.mbassy.listener.Invoke.Synchronously

      • priority

        int priority
        Handlers are ordered by priority and handlers with higher priority are processed before those with lower priority, i.e. Influence the order in which different handlers that consume the same message type are invoked.
        Default:
        0

      • rejectSubtypes

        boolean rejectSubtypes
        Define whether or not the handler accepts sub types of the message type it declares in its signature.
        Default:
        false

      • enabled

        boolean enabled
        Enable or disable the handler. Disabled handlers do not receive any messages. This property is useful for quick changes in configuration and necessary to disable handlers that have been declared by a superclass but do not apply to the subclass
        Default:
        true

      • invocation

        java.lang.Class<? extends HandlerInvocation> invocation
        Each handler call is implemented as an invocation object that implements the invocation mechanism. The basic implementation uses reflection and is the default. It is possible though to provide a custom invocation to add additional logic. Note: Providing a custom invocation will most likely reduce performance, since the JIT-Compiler can not do some of its sophisticated byte code optimizations.
        Default:
        net.engio.mbassy.dispatch.ReflectiveHandlerInvocation.class