org.apache.mina.handler.demux

Class DemuxingIoHandler

java.lang.Object

org.apache.mina.core.service.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 addReceivedMessageHandler(Class, MessageHandler) and removeReceivedMessageHandler(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 addReceivedMessageHandler(Class, MessageHandler) and removeReceivedMessageHandler(Class) clear this cache.

Author:

Apache MINA Project

Constructor Summary

Constructors

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

Method Summary

Methods

Modifier and Type	Method and Description
<E extends Throwable> ExceptionHandler<? super E>	addExceptionHandler(Class<E> type, ExceptionHandler<? super E> handler) Registers a MessageHandler that receives the messages of the specified type.
<E> MessageHandler<? super E>	addReceivedMessageHandler(Class<E> type, MessageHandler<? super E> handler) Registers a MessageHandler that handles the received messages of the specified type.
<E> MessageHandler<? super E>	addSentMessageHandler(Class<E> type, MessageHandler<? super E> handler) Registers a MessageHandler that handles the sent messages of the specified type.
void	exceptionCaught(IoSession session, Throwable cause) Invoked when any exception is thrown by user IoHandler implementation or by MINA.
protected ExceptionHandler<Throwable>	findExceptionHandler(Class<? extends Throwable> type)
protected MessageHandler<Object>	findReceivedMessageHandler(Class<?> type)
protected MessageHandler<Object>	findSentMessageHandler(Class<?> type)
Map<Class<?>,ExceptionHandler<?>>	getExceptionHandlerMap()
<E> MessageHandler<? super E>	getMessageHandler(Class<E> type)
Map<Class<?>,MessageHandler<?>>	getReceivedMessageHandlerMap()
Map<Class<?>,MessageHandler<?>>	getSentMessageHandlerMap()
void	messageReceived(IoSession session, Object message) Forwards the received events into the appropriate MessageHandler which is registered by addReceivedMessageHandler(Class, MessageHandler).
void	messageSent(IoSession session, Object message) Invoked when a message written by IoSession.write(Object) is sent out.
<E extends Throwable> ExceptionHandler<? super E>	removeExceptionHandler(Class<E> type) Deregisters a MessageHandler that receives the messages of the specified type.
<E> MessageHandler<? super E>	removeReceivedMessageHandler(Class<E> type) Deregisters a MessageHandler that handles the received messages of the specified type.
<E> MessageHandler<? super E>	removeSentMessageHandler(Class<E> type) Deregisters a MessageHandler that handles the sent messages of the specified type.

Methods inherited from class org.apache.mina.core.service.IoHandlerAdapter

inputClosed, 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

addReceivedMessageHandler

public <E> MessageHandler<? super E> addReceivedMessageHandler(Class<E> type,
                                                      MessageHandler<? super E> handler)

Registers a MessageHandler that handles the received messages of the specified type.

Type Parameters:

E - The message handler's type

Parameters:

type - The message's type

handler - The message handler

Returns:

the old handler if there is already a registered handler for the specified type. null otherwise.

removeReceivedMessageHandler

public <E> MessageHandler<? super E> removeReceivedMessageHandler(Class<E> type)

Deregisters a MessageHandler that handles the received messages of the specified type.

Type Parameters:

E - The message handler's type

Parameters:

type - The message's type

Returns:

the removed handler if successfully removed. null otherwise.

addSentMessageHandler

public <E> MessageHandler<? super E> addSentMessageHandler(Class<E> type,
                                                  MessageHandler<? super E> handler)

Registers a MessageHandler that handles the sent messages of the specified type.

Type Parameters:

E - The message handler's type

Parameters:

type - The message's type

handler - The message handler

Returns:

the old handler if there is already a registered handler for the specified type. null otherwise.

removeSentMessageHandler

public <E> MessageHandler<? super E> removeSentMessageHandler(Class<E> type)

Deregisters a MessageHandler that handles the sent messages of the specified type.

Type Parameters:

E - The message handler's type

Parameters:

type - The message's type

Returns:

the removed handler if successfully removed. null otherwise.

addExceptionHandler

public <E extends Throwable> ExceptionHandler<? super E> addExceptionHandler(Class<E> type,
                                                                    ExceptionHandler<? super E> handler)

Registers a MessageHandler that receives the messages of the specified type.

Type Parameters:

E - The message handler's type

Parameters:

type - The message's type

handler - The Exception handler

Returns:

the old handler if there is already a registered handler for the specified type. null otherwise.

removeExceptionHandler

public <E extends Throwable> ExceptionHandler<? super E> removeExceptionHandler(Class<E> type)

Deregisters a MessageHandler that receives the messages of the specified type.

Type Parameters:

E - The Exception Handler's type

Parameters:

type - The message's type

Returns:

the removed handler if successfully removed. null otherwise.

getMessageHandler

public <E> MessageHandler<? super E> getMessageHandler(Class<E> type)

Type Parameters:

E - The message handler's type

Parameters:

type - The message's type

Returns:

the MessageHandler which is registered to process the specified type.

getReceivedMessageHandlerMap

public Map<Class<?>,MessageHandler<?>> getReceivedMessageHandlerMap()

Returns:

the Map which contains all messageType-MessageHandler pairs registered to this handler for received messages.

getSentMessageHandlerMap

public Map<Class<?>,MessageHandler<?>> getSentMessageHandlerMap()

Returns:

the Map which contains all messageType-MessageHandler pairs registered to this handler for sent messages.

getExceptionHandlerMap

public Map<Class<?>,ExceptionHandler<?>> getExceptionHandlerMap()

Returns:

the Map which contains all messageType-MessageHandler pairs registered to this handler.

messageReceived

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

Forwards the received events into the appropriate MessageHandler which is registered by addReceivedMessageHandler(Class, MessageHandler). Warning ! If you are to overload this method, be aware that you _must_ call the messageHandler in your own method, otherwise it won't be called. Invoked when a message is received.

Specified by:

messageReceived in interface IoHandler

Overrides:

messageReceived in class IoHandlerAdapter

Parameters:

session - The session that is receiving a message

message - The received message

Throws:

Exception - If we get an exception while processing the received message

messageSent

public void messageSent(IoSession session,
               Object message)
                 throws Exception

Invoked when a message written by IoSession.write(Object) is sent out. Warning ! If you are to overload this method, be aware that you _must_ call the messageHandler in your own method, otherwise it won't be called. Invoked when a message written by IoSession.write(Object) is sent out.

Specified by:

messageSent in interface IoHandler

Overrides:

messageSent in class IoHandlerAdapter

Parameters:

session - The session that has sent a full message

message - The sent message

Throws:

Exception - If we get an exception while processing the sent message

exceptionCaught

public void exceptionCaught(IoSession session,
                   Throwable cause)
                     throws Exception

Invoked when any exception is thrown by user IoHandler implementation or by MINA. If cause is an instance of IOException, MINA will close the connection automatically. Warning ! If you are to overload this method, be aware that you _must_ call the messageHandler in your own method, otherwise it won't be called. Invoked when any exception is thrown by user IoHandler implementation or by MINA. If cause is an instance of IOException, MINA will close the connection automatically.

Specified by:

exceptionCaught in interface IoHandler

Overrides:

exceptionCaught in class IoHandlerAdapter

Parameters:

session - The session for which we have got an exception

cause - The exception that has been caught

Throws:

Exception - If we get an exception while processing the caught exception

findReceivedMessageHandler

protected MessageHandler<Object> findReceivedMessageHandler(Class<?> type)

findSentMessageHandler

protected MessageHandler<Object> findSentMessageHandler(Class<?> type)

findExceptionHandler

protected ExceptionHandler<Throwable> findExceptionHandler(Class<? extends Throwable> type)