Package org.apache.mina.handler.demux

Class DemuxingIoHandler

java.lang.Object

org.apache.mina.common.IoHandlerAdapter

org.apache.mina.handler.demux.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 Summary

Constructors

Constructor	Description
DemuxingIoHandler()	Creates a new instance with no registered MessageHandlers.

Method Summary

Modifier and Type	Method	Description
<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.
protected MessageHandler<java.lang.Object>	findHandler(java.lang.Class type)
<E> MessageHandler<? super E>	getMessageHandler(java.lang.Class<E> type)	Returns the MessageHandler which is registered to process the specified type.
java.util.Map<java.lang.Class,MessageHandler>	getMessageHandlerMap()	Returns the Map which contains all messageType-MessageHandler pairs registered to this handler.
void	messageReceived(IoSession session, java.lang.Object message)	Forwards the received events into the appropriate MessageHandler which is registered by addMessageHandler(Class, MessageHandler).
<E> MessageHandler<? super E>	removeMessageHandler(java.lang.Class<E> type)	Deregisters a MessageHandler that receives the messages of the specified type.

Methods inherited from class org.apache.mina.common.IoHandlerAdapter

exceptionCaught, messageSent, sessionClosed, sessionCreated, sessionIdle, sessionOpened

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

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.

messageReceived

public void messageReceived(IoSession session,
                            java.lang.Object message)
                     throws java.lang.Exception

Forwards the received events into the appropriate MessageHandler which is registered by addMessageHandler(Class, MessageHandler).

Specified by:

messageReceived in interface IoHandler

Overrides:

messageReceived in class IoHandlerAdapter

Throws:

java.lang.Exception

findHandler

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