import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

public class isUserExisting extends HttpServlet {
//Initialize global variables
  DBServerInterface dbm;

  public void init(ServletConfig config) throws ServletException {
    try{
      super.init(config);
      dbm = (DBServerInterface)System.getProperties().get("MDM.DBServer");
    }
    catch(Exception ex){
      ex.printStackTrace();
    }
  }

  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    PrintWriter out = new PrintWriter (response.getOutputStream());
    try{
      response.setContentType("text/html");
      String userName = request.getParameter("userName");
//JDBC routine to check user exists. If success then return
      boolean isUserExisting = dbm.isUserExisting(userName);
      if (isUserExisting){
        out.println("Success: Valid user. MDMessenger Initialising...");
      }
//If routine fails then return failure
      else{
        out.println("Failure");
      }
    }
    catch(NullPointerException ex){
        try{
          System.out.println("Recreating connection to FMServer");
          org.omg.CORBA.ORB orb = org.omg.CORBA.ORB.init();
          dbm = DBServerInterfaceHelper.bind(orb, "DBServer");
          System.getProperties().put("MDM.DBServer", dbm);
        }
        catch(Exception subEx){
          subEx.printStackTrace();
        }
    }
    catch(ClassCastException ex){
        try{
          System.out.println("Recreating connection to FMServer");
          org.omg.CORBA.ORB orb = org.omg.CORBA.ORB.init();
          dbm = DBServerInterfaceHelper.bind(orb, "DBServer");
          System.getProperties().put("MDM.DBServer", dbm);
        }
        catch(Exception subEx){
          subEx.printStackTrace();
        }
    }
    catch(Exception ex){
      ex.printStackTrace();
    }
    finally{
      out.close();
    }
  }

  public void destroy(){
    try{
      dbm = null;
    }
    catch(Exception ex){
      ex.printStackTrace();
    }
  }  
//Get Servlet information
  
  public String getServletInfo() {
    return "isUserExisting Information";
  }
}