/** *****************************************************************
TwoButtons.java SWE 642 servlet example
@author Jeff Offutt
@version 1.0 (3/6/02)
********************************************************************* */
// Import Java Libraries
import java.io.*;
import java.util.*;
//Import Servlet Libraries
import javax.servlet.*;
import javax.servlet.http.*;
// TwoButtons class
// CONSTRUCTOR: no constructor specified (default)
//
// *************** PUBLIC OPERATIONS **********************************
// public void doPost () --> prints a blank HTML page
// public void doGet () --> prints a blank HTML page
// private void PrintHead (PrintWriter out) --> Prints the HTML head section
// private void PrintBody (PrintWriter out) --> Prints the HTML body with
// the form. Fields are blank.
// private void PrintBody (PrintWriter out, String lhs, String rhs, String rslt)
// Prints the HTML body with the form.
// Fields are filled from the parameters.
// private void PrintTail (PrintWriter out) --> Prints the HTML bottom
//***********************************************************************
public class TwoButtons extends HttpServlet
{
// Location of servlet.
static String Domain = "ise.gmu.edu:8080";
static String Path = "/offutt/servlet/";
static String Servlet = "TwoButtons";
// Button labels
static String OperationAdd = "Add";
static String OperationSub = "Subtract";
// Other strings.
static String Style ="http://www.ise.gmu.edu/faculty/ofut/classes/642/642-style.css";
/** *****************************************************
* Overrides HttpServlet's doPost().
* Converts the values in the form, performs the operation
* indicated by the submit button, and sends the results
* back to the client.
********************************************************* */
public void doPost (HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
Float rslt = new Float (0.0);
Float lhsVal = new Float (0.0);
Float rhsVal = new Float (0.0);
String operation = request.getParameter ("Operation");
String lhsStr = request.getParameter ("LHS");
String rhsStr = request.getParameter ("RHS");
if ((lhsStr != null) && (lhsStr.length() > 0))
lhsVal = new Float (lhsStr);
if ((rhsStr != null) && (rhsStr.length() > 0))
rhsVal = new Float (rhsStr);
if (operation.equals (OperationAdd))
{
rslt = new Float (lhsVal.floatValue() + rhsVal.floatValue());
}
else if (operation.equals (OperationSub))
{
rslt = new Float (lhsVal.floatValue() - rhsVal.floatValue());
}
response.setContentType ("text/html");
PrintWriter out = response.getWriter();
PrintHead (out);
PrintBody (out, lhsStr, rhsStr, rslt.toString());
PrintTail (out);
} // End doPost
/** *****************************************************
* Overrides HttpServlet's doGet().
* Prints an HTML page with a blank form.
********************************************************* */
public void doGet (HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException
{
response.setContentType ("text/html");
PrintWriter out = response.getWriter();
PrintHead (out);
PrintBody (out);
PrintTail (out);
} // End doGet
/** *****************************************************
* Prints the of the HTML page, no .
********************************************************* */
private void PrintHead (PrintWriter out)
{
out.println ("");
out.println ("");
out.println ("");
out.println ("Name");
out.println (" ");
out.println ("");
out.println ("");
} // End PrintHead
/** *****************************************************
* Prints the of the HTML page with the form data
* values from the parameters.
********************************************************* */
private void PrintBody (PrintWriter out, String lhs, String rhs, String rslt)
{
out.println ("");
out.println ("
");
out.println ("A simple example that demonstrates how to operate with");
out.println ("multiple submit buttons.");
out.println ("
");
out.print ("");
out.println ("");
out.println ("");
} // End PrintBody
/** *****************************************************
* Overloads PrintBody(out,lhs,rhs,rslt) to print a page
* with blanks in the form fields.
********************************************************* */
private void PrintBody (PrintWriter out)
{
PrintBody (out, "", "", "");
}
/** *****************************************************
* Prints the bottom of the HTML page.
********************************************************* */
private void PrintTail (PrintWriter out)
{
out.println ("");
out.println ("
");
out.println ("Jeff Offutt, March 2002");
out.println ("
");
out.println ("");
} // End PrintTail
} // End TwoButtons