Class DemuxingIoHandler

  • All Implemented Interfaces:
    IoHandler

    public class DemuxingIoHandler
    extends IoHandlerAdapter
    A IoHandler that demuxes messageReceived events to the appropriate MessageHandler.

    You can freely register and deregister MessageHandlers using addMessageHandler(Class, MessageHandler) and removeMessageHandler(Class).

    When message is received through a call to messageReceived(IoSession, Object) the class of the message object will be used to find a MessageHandler for that particular message type. If no MessageHandler instance can be found for the immediate class (i.e. message.getClass()) the interfaces implemented by the immediate class will be searched in depth-first order. If no match can be found for any of the interfaces the search will be repeated recursively for the superclass of the immediate class (i.e. message.getClass().getSuperclass()).

    Consider the following type hierarchy (Cx are classes while Ix are interfaces):

         C3 - I7 - I9
          |    |   /\
          |   I8  I3 I4
          |
         C2 - I5 - I6
          |
         C1 - I1 - I2 - I4
          |         |
          |        I3
        Object          
     
    When message is of type C3 this hierarchy will be searched in the following order: C3, I7, I8, I9, I3, I4, C2, I5, I6, C1, I1, I2, I3, I4, Object.

    For efficiency searches will be cached. Calls to addMessageHandler(Class, MessageHandler) and removeMessageHandler(Class) clear this cache.

    • Constructor Detail

      • DemuxingIoHandler

        public DemuxingIoHandler()
        Creates a new instance with no registered MessageHandlers.
    • Method Detail

      • addMessageHandler

        public <E> MessageHandler<? super E> addMessageHandler​(java.lang.Class<E> type,
                                                               MessageHandler<? super E> handler)
        Registers a MessageHandler that receives the messages of the specified type.
        Returns:
        the old handler if there is already a registered handler for the specified type. null otherwise.
      • removeMessageHandler

        public <E> MessageHandler<? super E> removeMessageHandler​(java.lang.Class<E> type)
        Deregisters a MessageHandler that receives the messages of the specified type.
        Returns:
        the removed handler if successfully removed. null otherwise.
      • getMessageHandler

        public <E> MessageHandler<? super E> getMessageHandler​(java.lang.Class<E> type)
        Returns the MessageHandler which is registered to process the specified type.
      • getMessageHandlerMap

        public java.util.Map<java.lang.Class,​MessageHandler> getMessageHandlerMap()
        Returns the Map which contains all messageType-MessageHandler pairs registered to this handler.
      • findHandler

        protected MessageHandler<java.lang.Object> findHandler​(java.lang.Class type)