org.apache.mina.handler.chain
Interface IoHandlerCommand

All Known Implementing Classes:

IoHandlerChain

public interface IoHandlerCommand

A IoHandlerCommand encapsulates a unit of processing work to be performed, whose purpose is to examine and/or modify the state of a transaction that is represented by custom attributes provided by IoSession. Individual IoHandlerCommands can be assembled into a IoHandlerChain, which allows them to either complete the required processing or delegate further processing to the next IoHandlerCommand in the IoHandlerChain.

IoHandlerCommand implementations typically retrieve and store state information in the IoSession that is passed as a parameter to the execute(NextCommand,IoSession,Object) method, using custom session attributes. If you think getting attributes is tedious process, you can create a bean which contains getters and setters of all properties and store the bean as a session attribute:

 public class MyContext {
   public String getPropertyX() { ... };
   public void setPropertyX(String propertyX) { ... };
   public int getPropertyZ() { ... };
   public void setPropertyZ(int propertyZ) { ... };
 }

 public class MyHandlderCommand implements IoHandlerCommand {
   public void execute( NextCommand next, IoSession session, Object message ) throws Exception {
     MyContext ctx = session.getAttribute( "mycontext" );
     ...
   }
 }
 

Author:

Apache MINA Project

Nested Class Summary

static interface

IoHandlerCommand.NextCommand Represents an indirect reference to the next IoHandlerCommand of the IoHandlerChain.

Method Summary

void	execute(IoHandlerCommand.NextCommand next, IoSession session, Object message) Execute a unit of processing work to be performed.

Method Detail

execute

void execute(IoHandlerCommand.NextCommand next,
             IoSession session,
             Object message)
             throws Exception

Execute a unit of processing work to be performed. This IoHandlerCommand may either complete the required processing and just return to stop the processing, or delegate remaining processing to the next IoHandlerCommand in a IoHandlerChain containing this IoHandlerCommand by calling IoHandlerCommand.NextCommand.execute(IoSession,Object).

Parameters:

next - an indirect reference to the next IoHandlerCommand that provides a way to forward the request to the next IoHandlerCommand.

session - the IoSession which is associated with this request

message - the message object of this request

Throws:

Exception - general purpose exception return to indicate abnormal termination