Hi Folks,
I finally have done developing a JSP query application. I need ur experts
advice on the following code I have written that hopefully I havent written
anything illegal(in terms of designing this thing) or if it is a poor/good
way of doing things in JSP environment.
Greatly appreciate any help..thanx in advance
Heres the code for my LoginBean(in the jsp page the scope of this bean is
application):
import javax.servlet.http.*;
import java.util.*;
public class LoginBean implements HttpSessionBindingListener{
String username;
String password;
String dbInstance;
String status = new String("Not Connected");
static Hashtable h;
/****** Bean Properties ******/
set and get methods for username, pwd, dbInstance
/****** End: Bean Properties ******/
// param: "session" Object from JSP Page
public void processSession(HttpSession session) {
String sessionID;
DBManager dbm;
//DBManager is a bean that manages all my database related
tasks
// one per each user session
if (h==null){
h = new Hashtable();
}
sessionID = session.getId();
if (h.containsKey(sessionID)) {
System.out.println("Session Already
Created:"+sessionID);
}
else{
dbm = new DBManager();
//returns connected if successful else the exception
message
status = dbm.connect(username,password,dbInstance);
if (status.equalsIgnoreCase("Connected")){
h.put(sessionID,dbm);
System.out.println("Added:" + sessionID);
//I did this because I wanted the LoginBean
to be notified when the session
//gets invalidated
//Should I have created a seperate object
which implemented
//HttpSessionBindingListener and then do the
cleanup there
//instead of puttin my LoginBean in
session??????
session.putValue("login",this); // IS THIS
GOOD APPROACH???
session.putValue("loginID",username);
}
else
//display the exception
}
}
public String getStatus(){
return status;
}
public DBManager getDBManager(String sessionID){
return (DBManager)h.get(sessionID); //will put code
to handle if sessionID is not in the Hashtable
}
/*
valueUnbound: Gets Invoked when the LoginBean is removed from the
session
or the session gets invalidated
Closes Database Connection
and Removes the SessionID from the
Hashtable
*/
public void valueUnbound(HttpSessionBindingEvent event){
DBManager dbm;
System.out.println("I just got UN-Bounded for
SessionID"+event.getSession().getId());
//will put code to handle if sessionID is not in the
Hashtable
dbm = getDBManager(event.getSession().getId()); //gets the
DB Connection for the particular session getting invalidated
dbm.close();
dbm=null;
h.remove(event.getSession().getId());
}
protected void finalize() throws Throwable{
System.out.println("In Finalize of
LoginBean..."+this.toString());
}
}
Later in my application I use the implicit "application" object to get the
login bean and from login bean I get the DBManager Instance(for sessionID)
and do some tasks like perform a query to database and display result etc.
Is this whole approach a good idea or a very bad one???? Need your expert
advice!!
Asim Imam
Application Developer
@AT&T Tax Systems Group
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