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):
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.