Customer Balance Information

/*
 * @(#)CustomerInfo.java
 *
 * Copyright (c) 1998 Karl Moss. All Rights Reserved.
 *
 * You may study, use, modify, and distribute this software for any
 * purpose provided that this copyright notice appears in all copies.
 *
 * This software is provided WITHOUT WARRANTY either expressed or
 * implied.
 *
 * @author  Karl Moss
 * @version 1.0
 * @date    15May98
 *
 */

package javaservlets.rmi;

import javax.servlet.*;
import javax.servlet.http.*;
import javaservlets.rmi.server.*;

/**
 * <p>This is a simple servlet that will return customer
 * information. Note that this servlet implements the
 * SingleThreadModel interface which will force the Web browser
 * to synchronize all requests
 */

public class CustomerInfo
  extends HttpServlet
  implements SingleThreadModel
{
  /**
    * <p>Performs the HTTP POST operation
    *
    * @param req The request from the client
    * @param resp The response from the servlet
    */

  public void doPost(HttpServletRequest req,
                     HttpServletResponse resp)
    throws ServletException, java.io.IOException
    {

      // Create a PrintWriter to write the response
      java.io.PrintWriter out =
        new java.io.PrintWriter(resp.getOutputStream());

      // Set the content type of the response
      resp.setContentType("text/html");

      // Print the HTML header
      out.println("<html>");
      out.println("<head>");
      out.println("<title>Customer Balance Information</title>");
      out.println("</head>");
      
      // Get the Customer id
      String id = null;
      String values[] = req.getParameterValues("CustomerID");
      if (values != null) {
        id = values[0];
      }

      // The target host. Change to 'rmi://yourhost/' when the
      // server runs on a remote machine
      String host = "";

      try {

        // Attempt to bind to the remote host and get the
        // instance of the Customer object
        CustomerInterface cust = (CustomerInterface)
          java.rmi.Naming.lookup(host + "Customer");

        // We have an instance of the remote object. Get the
        // customer information
        CustomerData data = cust.getCustomerData(id);

        // Format the HTML
        out.println("The current balance for " + data.name +
                    " is $" + data.balance);
      }
      catch (Exception ex) {

        // Turn exceptions into a servlet exception
        ex.printStackTrace();
        throw new ServletException(ex.getMessage());
      }

      // Wrap up
      out.println("</html>");
      out.flush();
      out.close();
    }

  /**
    * <p>Initialize the servlet. This is called once when the
    * servlet is loaded. It is guaranteed to complete before any
    * requests are made to the servlet
    *
    * @param cfg Servlet configuration information
    */

  public void init(ServletConfig cfg)
    throws ServletException
    {
      super.init(cfg);
    }

  /**
    * <p>Destroy the servlet. This is called once when the servlet
    * is unloaded.
    */

  public void destroy()
    {
      super.destroy();
    }
}