Arnav Mitra

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since Oct 12, 2007

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Recent posts by Arnav Mitra

Design Patterns...

Oh it was not at all a dumb question. "No questions are dumb" that's what K&B's Head First says right?

Cheers,

Arnav.

17 years ago

OO, Patterns, UML and Refactoring

Design Patterns...

Can you please tell more about what you are trying to achieve? The purpose of Factory, Decorator and Strategy are different. The use of interfaces alone does not make a Factory, Decorator or Strategy and they belong to different genre.

Factory: Creates an instance of several families of classes. [A Creational Pattern]

Decorator: Add responsibilities to objects dynamically [Structural Pattern]

Strategy: Encapsulates an algorithm inside a class. [Behavioral Pattern]

Check this online resource out, its quite simple and friendly: http://sourcemaking.com/design_patterns

Characteristics of Decorator:

The Decorator Pattern is used to extend the functionality of an object dynamically without having to change the original class source or using inheritance. This is accomplished by creating an object wrapper referred to as a Decorator around the actual object. That ways decorator is an alternative to using inheritance.

The Decorator object is designed to have the same interface as the

underlying object. This allows a client object to interact with the Decorator
object in exactly the same manner as it would with the underlying
actual object.

The Decorator object contains a reference to the actual object.

The Decorator object receives all requests (calls) from a client. It in turn forwards these calls to the underlying object

The Decorator object adds some additional functionality before or after

forwarding requests to the underlying object. This ensures that the additional functionality can be added to a given object externally at runtime without modifying its structure.

Strategy Pattern

The Strategy pattern is useful when there is a set of related algorithms and a client object needs to be able to dynamically pick and choose an algorithm from this set that suits its current need.

Well...!!! I guess this short introduction will probably help you a little. From your code it seems you have something related to dynamic behavior. Just be sure what you are trying to achieve and often Design Patterns are used in conjunction to each other.

[ May 01, 2008: Message edited by: Arnav Mitra ]

17 years ago

OO, Patterns, UML and Refactoring

J2EE and Servlets

Here is a small application that helps you to post your skills into a database also it offers an option to cut-paste a part of your resume.

It uses a simple HttpServlet, a DAO and HTML. Hope it gives you some insight to the Servlet API. I'll share the code here.

The DAO

package com.iacsys.jobsmart;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class ResumeDAO
{
Connection conn;
Statement stmt;
ResultSet rs;
String urlString = "jdbc :-o racle:thin:@127.0.0.1:1521:MyOracle";
String username = "scott";
String password = "tiger";
public void getConnected()
{
try
{
Class.forName("oracle.jdbc.driver.OracleDriver");
conn = DriverManager.getConnection(urlString , username, password);
stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
conn.setReadOnly(false);
}
catch(ClassNotFoundException cnfe)
{
cnfe.printStackTrace();
}
catch(SQLException sqle)
{
sqle.printStackTrace();
}
}
public void insertInfo(String fn, String mn, String ln, String sex, String city, String sS, String desc)
{
String updateString = "insert into resumes values(resume_ref_Id.NEXTVAL," + " '" + fn + "', '" + mn + "', " + "'" + ln + "', '" + sex + "', '" + city + "', '" + sS + "', '" + desc + "')";
try
{
stmt.executeUpdate(updateString);
conn.commit();
stmt.close();
}
catch (SQLException e)
{
e.printStackTrace();
}
}
public String getReferenceNo()
{
String queryString = "Select REF_ID from resumes";
String referenceNo = "";
try
{
stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
rs = stmt.executeQuery(queryString);
rs.last();
referenceNo = rs.getString(1);
}
catch (SQLException e)
{
e.printStackTrace();
}
return referenceNo;
}
}

package com.iacsys.jobsmart;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class PostResume extends HttpServlet
{
private static final long serialVersionUID = 3718380143289904378L;
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String fName = request.getParameter("fName");
String mName = request.getParameter("mName");
String lName = request.getParameter("lName");
String gender = request.getParameter("genderRadio");
String citySelect = request.getParameter("CitySelect");
String description =request.getParameter("DescriptionText");
String[] skills = request.getParameterValues("checkbox1");
String skillSet = "";
for(int i = 0; i < skills.length; i++)
{
skillSet += (skills[i] + ", ");
}
ResumeDAO dataAccesor = new ResumeDAO();
dataAccesor.getConnected();
dataAccesor.insertInfo(fName, mName, lName, gender, citySelect, skillSet, description);
out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<HTML>");
out.println("<HEAD><TITLE>JobSmart: You Made a Smart Choice</TITLE></HEAD>");
out.println("<BODY>");
out.println("<h2>Your Resume has been posted!,,</h2><h4><i> thank you for choosing JobSmart.</i></h4>");
out.println("First Name: " + fName + "<br>");
out.println("Middle Name: " + mName + "<br>");
out.println("Last Name: " + lName + "<br>");
out.println("Sex: " + gender + "<br>");
out.println("Your Skill Set: " + skillSet + "<br>");
out.println("<br>");
out.println("City of Preference: " + citySelect + "<br>");
out.println("Description: " + description + "<br>");
out.println("<h5>For future correspondence quote this reference Number: " + dataAccesor.getReferenceNo() + " </h5>");
out.println("</BODY>");
out.println("</HTML>");
out.flush();
out.close();
}
}

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>JobSmart.com :-P ost your Resume the smart way..!!!</title>
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">

</head>
<body><br><br><body bgcolor = "lightBlue">
<form action = "servlet/PostResume">
<h1><b><i><marquee>Hi!!!.. Welcome to JobSmart, The smartest way to get hired.</marquee></i></b></h1>
<div align="left"><font face="Arial Unicode MS">First Name:</font>
    
<input type="text" maxlength="30" name="fName"><br></div>
<br><font face="Arial Unicode MS">Middle Name:</font> 
<input type="text" maxlength="30" name="mName"><br>
<br><font face="Arial Unicode MS">Last Name: </font>
   
<input type="text" maxlength="30" name="lName"><br>
<br>
<em><font face="Arial Unicode MS">Gender:</font>
 </em>
    
<input type="radio" value="Male" name="genderRadio">
   
<em><font face="Arial Unicode MS">Male</font></em>
   
<input type="radio" value="Female" name="genderRadio">
   
<em><font face="Arial Unicode MS">Female<br>
City:   </font></em><select name="CitySelect">
<option value="NULL">--Select City--</option>
<option value="AHM">Ahmedabad</option>
<option value="BLR">Bangalore</option>
<option value="BBSR">Bhubaneswar</option>
<option value="CHE">Chennai</option>
<option value="GUR">Gurgaon</option>
<option value="HYD">Hyderabad</option>
<option value="KOL">Kolkata</option>
<option value="MAN">Mangalore</option>
<option value="MUM">Mumbai</option>
<option value="MYS">Mysore</option>
<option value="DEL">New Delhi</option>
<option value="NOI">Noida</option>
<option value="PUN">Pune</option>
<option value="RAN">Ranchi</option>
<option value="RKL">Rourkela</option>
</select>
<br><em><font face="Arial Unicode MS">Skills:   <br></font></em>
<input type="checkbox" value="Java" name="checkbox1">
   
<font face="Arial Unicode MS"> Java<br></font>
<input type="checkbox" value="J2EE" name="checkbox1">
   
<font face="Arial Unicode MS"> J2EE<br></font>
<input type="checkbox" value=".NET" name="checkbox1">
   
<font face="Arial Unicode MS">.NET<br></font>
<input type="checkbox" value="ABAP" name="checkbox1">
   
<font face="Arial Unicode MS">ABAP<br></font>
<input type="checkbox" value="C++" name="checkbox1">
   
<font face="Arial Unicode MS">C++<br></font>
<input type="checkbox" value="C#" name="checkbox1">
   
<font face="Arial Unicode MS">C#</font><br>
<input type="checkbox" value="C" name="checkbox1">
   
<font face="Arial Unicode MS">C</font><br>
<input type="checkbox" value="Oracle" name="checkbox1">
   
<font face="Arial Unicode MS">Oracle PL/SQL<br><br>
Description:<br><br></font>
<textarea wrap="hard" cols="40" rows="4" name="DescriptionText">
Cut and Paste your Resume here
</textarea><br>
<font face="Arial Unicode MS"><br></font>
<div align="center">
<font face="Arial Unicode MS">
      
     
     
   
</font><input type="submit" value="SubmitResume" name="SubmitButton">
   
<input type="reset" value="Reset" name="ResetButton">
<font face="Arial Unicode MS">
   <br>    
        
</font></div>
</body>
</html>

web.xml

17 years ago

Servlets

Struts Based CRM project your Learners

I am working on a Struts Based CRM project right now and would be releasing it for people who want to learn Struts with real world examples and real use cases.

17 years ago

Struts

J2EE and Servlets

Originally posted by Angela D'souza:
Hi,
I was working in J2EE and Servlet for four years in 2004. After that, due to my son medical condition i resigned job. Then after i didn't any work on java for 3 yrs now. I want to do practice so i can apply again in market. Can anyone let me know good user friendly tutorials on Java (setup, coding etc for J2EE) through which i can learn fast.
Also which version is latest in J2EE, Tomcat, Webshere, Weblogic in market?
Thank You,
Angela

[ February 21, 2008: Message edited by: Angela D'souza ]

There are some nice tutorials at coreservlets.com specially Marty Hall's.
If feel Marty Hall is a great author, besides him you can go for SCWCD by Hanumant deshmukh.
[ February 27, 2008: Message edited by: David O'Meara ]

17 years ago

Servlets