Running servlet from bean

[Dilip kumar]

Hi,
We have
01. Data access class ( bean ) to connect to database, execute query and return recordset.
02. Class ( bean ) which prepares the dynamic SQL statement based on business logic. This class calls Data access class methods to connect to database, prepare statement and execute.
To improve the performance we would like to add database connection pool in Data access class (bean). Since Servlet�s INIT menthod is the best palce to create connection pool we are planning to make Data access class servlet instead of bean.
My question is can we run the servlet from class ( bean ) mentioned in #2. For testing purpose I tried the following code but it�s not working.
import javax.servlet.*;
import javax.servlet.http.*;
class Servlet1 extends HttpServlet {
String message;
public void init(ServletConfig config) throws ServletException {
message = "Done";
}
public void displayMessage () {
System.out.println(message);
}
}
public class ServletTest {
public static void main(String args[]) {
Servlet1 S = new Servlet1();
S.displayMessage();
}
}
Thanks
Dilip

[maha anna]

Dilip,
I think it is the other way round. Write your connectionPool as a Java class and test independently. Now in all your servlets which want to share a connectionPool object, do this logic.
In all servlet's init() check if there is a ConnectionPool obj in servletContext. If it is not there, then create a ConnecitonPool and sponsor to other servlets which are in same web application also by putting in ServletContext.
The same procedure is done in all other servlet's init(). So whichever servlet sees first time , there is no common ConnectionPool in sevlet context, creates a fresh one and delegates to others. From then onwards, others will just use the connection pool. This procedure I used and found it useful.

//In all servlet's init method put this code
public class LoginServlet extends HttpServlet implements AllConstants{
  private ConnectionPool connectionPool;
  public void init() {
System.out.println("init:Login Servlet loaded");
connectionPool = ServletUtilities.createConnectionPool(getServletContext(),"LoginServlet");
   }
}
//In servletUtilities.java
public static ConnectionPool createConnectionPool(ServletContext context,String createrServletName) {
  int vendor = AllConstants.VENDOR;
    String driver = DriverUtilities.getDriver(vendor);
    String host = AllConstants.HOST;
    String dbName = AllConstants.DBNAME;
    String url = DriverUtilities.makeURL(host, dbName, vendor);
    String username = AllConstants.USERID;
    String password = AllConstants.USERPASSWD;
    ConnectionPool connectionPool=null;
    try {
connectionPool = (ConnectionPool)context.getAttribute("connection-pool");
if(connectionPool == null) {
     System.out.println(""+driver+":"+url+":"+username+password);
   connectionPool = new ConnectionPool(driver, url, username, password,AllConstants.INITIAL_CONNECTIONS,AllConstants.MAX_CONNECTIONS,true);
  System.out.println("Creating Connection Pool and putting in ServletContext");
 context.setAttribute("connection-pool",connectionPool);
     }else {
System.out.println("Ha ha!! Someone already created the Connection pool!! I just use it!!");
     }
 } catch(SQLException sqle) {
      System.err.println("Error making pool: " + sqle);
      context.log("Error making pool: " + sqle);
     connectionPool= null;
}
return connectionPool;
}
*/