[Opensource] Swing client

[Turgay Zengin]

Thanks to everyone who helped me in this standalone client connecting to 
Expresso idea. I want to finalize what I had done, in hope that it can be 
helpful for others too.

I now have a servlet called "ExpressoClientInterfaceServlet" which handles 
all communications between the standalone client and Expresso. You can find 
the servlet code below.

The only remaining part is what you will return to the client - because the 
"ControllerResponse" class cannot be serialized - I guess this is because it 
contains lots of stuff that some of them are not serializable. So, one 
should construct what to send back to the client as a response and return 
it.

(Tsanko, you said before that there was no session to store user's info, but 
there is. With the help of re-sending the jsessionid each time to the 
server, the state information is preserved. I would like to hear your ideas 
on how to convert this to RMI, you said it would be a better way to go - 
please let me know offlist if you are interested)

Here is the servlet:

import com.jcorporate.expresso.core.controller.*;
import javax.servlet.http.*;
import javax.servlet.*;
import java.io.*;
import java.util.Properties;

public class ExpressoClientInterfaceServlet extends HttpServlet {

    //call the controller and return the ControllerResponse
    public ControllerResponse runState(HttpServletRequest request, String 
controller, String state)
    {
      try{
      	Controller myController = 
com.jcorporate.expresso.core.misc.ConfigManager.getControllerFactory().getController(controller);
        //we should send a ControllerRequest, so construct one
      	ControllerRequest cReq = 
ServletControllerRequest.parseParams(request,null,myController);
        //newState is where the work is done - including security check
      	return myController.newState(state,cReq);
      } catch (Exception e) { System.out.println(e.toString()); return null; 
}
    }

    //client request reaches here...
    public void doPost(HttpServletRequest request, HttpServletResponse 
response)
        throws ServletException, IOException {

        String controller = request.getParameter("controller");
        String state = request.getParameter("state");
        try {
	  ControllerResponse cRes = runState(request,controller,state);
          //here you should construct your own object from the 
ControllerResponse and send it to the client
	  ObjectOutputStream out = new 
ObjectOutputStream(response.getOutputStream());
	  YourResponse yourResponse = new YourResponse(cRes);
    	  out.writeObject(yourResponse);
          out.close();
        } catch(Exception e){
            System.out.println(e.toString());
        }
    }
}

And here is a possible client method to call the servlet:

private void btnGetDataActionPerformed(java.awt.event.ActionEvent evt) {
  // Add your handling code here:
  URL servlet = null;
  try{
  //remember that we had recorded the jSessionId before - when we logged 
on...
    servlet = new 
URL("http://hostname:port/servlet/ExpressoClientInterfaceServlet;jsessionid=" 
+ jSessionId);

    com.oreilly.servlet.HttpMessage msg = new 
com.oreilly.servlet.HttpMessage(servlet);
    Properties props = new Properties();
    //put all your request parameters and their values here
    props.put("stateParameter",parameterValue);
    ....
    ....
    //put in your controller's name and the state
    
props.put("controller","tr.com.atas.helpdesk.controller.EquipmentController"); 
       props.put("state","showEq");
    InputStream in = msg.sendPostMessage(props);
    ObjectInputStream oin = new ObjectInputStream(in);
    Object o = oin.readObject();
    oin.close();

    YourResponse serverResponse = (YourResponse) o;
    //now update your interface according to the values in the response 
object....
  } catch(Exception e) {
    System.out.println("Error:\n"+e.toString());
  }
}

I hope it's all clear, if not please let me know.

Regards,
Turgay Zengin.

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