Chapter 7 - Handler
Handles all I/O events fired by MINA. The interface is hub of all activities done at the end of the Filter Chain.
IoHandler has following functions
Session Created event is fired when a new connection is created. For TCP its the result of connection accept, and for UDP this is generated when a UDP packet is received. This function can be used to initialize session attributes, and perform one time activities for a particular connection.
This function is invoked from the I/O processor thread context, hence should be implemented in a way that it consumes minimal amount of time, as the same thread handles multiple sessions.
Session opened event is invoked when a connection is opened. Its is always called after sessionCreated event. If a thread model is configured, this function is called in a thread other than the I/O processor thread.
Session Closed event is closed, when a session is closed. Session cleaning activities like cash cleanup can be performed here.
Session Idle event is fired when a session becomes idle. This function is not invoked for UDP transport.
This functions is called, when an Exception is thrown by user code or by MINA. The connection is closed, if its an IOException.
Message Received event is fired whenever a message is received. This is where the most of the processing of an application happens. You need to take care of all the message type you expect here.
Message Sent event is fired, whenever a message aka response has been sent(calling IoSession.write()).