JAVA Spine

Use of Session Bean in RA

sudipkundu — Mon, 31 Mar 2008 06:42:01 +0000

ACTION
********

package mj.eps.action.business;

public class HelloAction extends DispatchAction
{
public ActionForward add(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception
{
ActionErrors errors = new ActionErrors();
ActionForward forward = new ActionForward();
HelloForm helloform = (HelloForm) form;
try
{
IService service = getService(request);
AuctionEjbDelegate auctionEjbDelegate = service.getAuctionEjbDelegate();
String ret = auctionEjbDelegate.getHello();
helloform.setName(ret);
//request.setAttribute(“HELLO”, ret);
}
catch (Exception e)
{
errors.add(“name”, new ActionError(“id”));
}
if (!errors.isEmpty())
{
saveErrors(request, errors);
forward = mapping.findForward(“failure”);
}
else
{
forward = mapping.findForward(“success”);
}
return (forward);
}
protected IService getService(HttpServletRequest request)
{
IService service = (IService) getSessionObject(request, IConstant.SERVICE_CONTAINER_KEY);
if (service == null)
{
service = new ServiceImplementation();
request.getSession().setAttribute(IConstant.SERVICE_CONTAINER_KEY, service);
}
return service;
}
protected Object getSessionObject(HttpServletRequest request, String attributeName)
{
Object sessionObject = null;
HttpSession session = request.getSession(true);
sessionObject = session.getAttribute(attributeName);
return sessionObject;
}
protected UserContainer getUserContainer(HttpServletRequest request)
{
UserContainer userContainer = (UserContainer) getSessionObject(request, IConstant.USER_CONTAINER_KEY);
if (userContainer == null)
{
userContainer = new UserContainer();
userContainer.setLocale(request.getLocale());
HttpSession session = request.getSession();
session.setAttribute(IConstant.USER_CONTAINER_KEY, userContainer);
}
return userContainer;
}
}

STRUTS-CONFIG
**************
name= “helloform”
parameter=”method”>

ACTION-FORM
***************
package mj.eps.form;

import org.apache.struts.action.ActionForm;

public class HelloForm extends ActionForm
{
public String name=”";

public HelloForm (){
super();
}

/**
* @return
*/
public String getName()
{
return name;
}

/**
* @param string
*/
public void setName(String string)
{
name = string;
}

}

JSP
***********************

<%@ taglib uri=”/WEB-INF/struts-html.tld” prefix=”html” %>
<%@ taglib uri=”/WEB-INF/struts-bean.tld” prefix=”bean” %>

<%@ page
language=”java”
contentType=”text/html; charset=ISO-8859-1″
pageEncoding=”ISO-8859-1″
%>

hello.jsp

******************************

import com.mj.eps.session.sudip.MySession;
import com.mj.eps.session.sudip.MySessionHome;

public class AuctionEjbDelegate
{
IAuction auctionFacade;
Auction auctionFacade1;
AuctionAdmin auctionAdminFacade;
MySession mySession;
TestSession test;
public AuctionEjbDelegate()
{
init();
}
private void init()
{
try
{
AuctionHome auctionFacadeHome = (AuctionHome) EJBHomeFactory.getInstance().lookupHome(IJNDIName.AUCTION_FACADE_HOME, AuctionHome.class);
auctionFacade = auctionFacadeHome.create();
auctionFacade1 = (Auction) auctionFacade;
AuctionAdminHome auctionAdminHome = (AuctionAdminHome) EJBHomeFactory.getInstance().lookupHome(IJNDIName.AUCTION_ADMIN_FACADE_HOME, AuctionAdminHome.class);
auctionAdminFacade = auctionAdminHome.create();
MySessionHome mySessionHome = (MySessionHome) EJBHomeFactory.getInstance().lookupHome(IJNDIName.MYSESSION_FACADE, MySessionHome.class);
mySession = (MySession) mySessionHome.create();

TestSessionHome testHome = (TestSessionHome) EJBHomeFactory.getInstance()
.lookupHome(IJNDIName.TEST_FACADE, TestSessionHome.class);
test = (TestSession) testHome.create();

}
catch (NamingException e)
{
throw new RuntimeException(e.getMessage());
}
catch (CreateException e)
{
throw new RuntimeException(e.getMessage());
}
catch (RemoteException e)
{
throw new RuntimeException(e.getMessage());
}
}

public String getHello()
{
try
{
return test.name();
}
catch (Exception e)
{
throw new RuntimeException(e.getMessage());
}
}
}

**************

SESSION BEAN
*************
THIS SESSION BEAN WILL CALL THE DB AND FETCH THE RESULTS USING “DATABASECONTROLLER.JAVA”
****************************************************************************************

package com.mj.eps.session.Test;

public class TestSessionBean implements javax.ejb.SessionBean
{
All other boiler-plate methods +

public String name(){
return “Hello-test”;
}
}

Remote interface for Enterprise Bean: TestSession
*************************************************

package com.mj.eps.session.Test;
public interface TestSession extends javax.ejb.EJBObject
{
public String name() throws java.rmi.RemoteException;
}

DispatchAction-example

sudipkundu — Mon, 31 Mar 2008 06:01:37 +0000

The major component in the Struts based application is the Action class. Action class only defines the next steps and logic processing for the application. The execute() method is called by the framework for the processing. All the business logic and all the flow is derived from the execute() method in the Action class. There is a special Action class which will permit the user to have more than one method which can be called by the framework and not just the execute() method. This class is DispatchAction. The class is helpful to have all the methods related to a single UI page in one Action class and developers need not to implement the logics in different classes. The method to be called on Action is decided with the parameter attribute in the tag of struts-config.xml. The code for the mapping is given below.

type=”com.visualbuilder.DispatchActionExample”
parameter=”method”
name=”inputForm”
input=”/index.jsp” />

Note:-The above mapping will check the method parameter and call the method with the name coming in the parameter. Add the following keys in the messageresources.properties file under WEB-INF/classes

error.unspecified= Unspecified Called.
error.add= Add Called.
error.delete= delete Called.
error.view= View Called.

Example For DispatchAction
***************************

(1) Struts-config.xml file
******************************

“http://struts.apache.org/dtds/struts-config_1_3.dtd”>

type=”com.visualbuilder.DispatchActionExample”
parameter=”method”
name=”inputForm”
input=”/index.jsp” />

(2) ActionForm Class
**********************

package com.visualbuilder;

import org.apache.struts.action.ActionForm;

public class InputForm extends ActionForm{

}

(3) ActionClass
*****************
Note:- Now all the action classes must imherit the org.apache.struts.action.DispatchAction Class and not the org.apache.struts.action.Action Class.

package com.visualbuilder;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.ActionMessages;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionMessage;
import org.apache.struts.action.ActionMessages;
import org.apache.struts.actions.DispatchAction;

public class DispatchActionExample extends DispatchAction{

protected ActionForward unspecified(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response)
throws Exception {
ActionMessages message = new ActionMessages();
message.add(“unspecified”,new ActionMessage(“error.unspecified”));
saveMessages(request, message);
return mapping.getInputForward();
}

public ActionForward view(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception{
ActionMessages message = new ActionMessages();
message.add(“unspecified”,new ActionMessage(“error.view”));
saveMessages(request, message);
return mapping.getInputForward();
}
public ActionForward add(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception{
ActionMessages message = new ActionMessages();
message.add(“unspecified”,new ActionMessage(“error.add”));
saveMessages(request, message);
return mapping.getInputForward();
}
public ActionForward delete(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {
ActionMessages message = new ActionMessages();
message.add(“unspecified”,new ActionMessage(“error.delete”));
saveMessages(request, message);
return mapping.getInputForward();
}

}

(4) JSP Page
**************
<%@ taglib uri=”http://struts.apache.org/tags-bean” prefix=”bean” %>
<%@ taglib uri=”http://struts.apache.org/tags-html” prefix=”html” %>
<%@ taglib uri=”http://struts.apache.org/tags-logic” prefix=”logic” %>

Submit for add

Submit for view

Submit for delete

Submit for unspecified

struts-Reverse Auction (RA)

sudipkundu — Mon, 31 Mar 2008 06:00:36 +0000

ACTION CLASS
*************

public class HelloAction extends EPSBaseAction
{
public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception
{
ActionErrors errors = new ActionErrors();
ActionForward forward = new ActionForward();
HelloForm helloform = (HelloForm)form;
try
{
IService service = getService(request);
AuctionEjbDelegate auctionEjbDelegate = service.getAuctionEjbDelegate();
String ret = auctionEjbDelegate.getHello();
helloform.setName(“HELLO-SUDIP”);
request.setAttribute(“HELLO”, ret);

}
catch (Exception e)
{
errors.add(“name”, new ActionError(“id”));
}
if (!errors.isEmpty())
{
saveErrors(request, errors);
forward = mapping.findForward(“failure”);
}
else
{
forward = mapping.findForward(“success”);
}
return (forward);
}
}

STRUTS-CONFIG
*************

FORM BEAN
*********

public class HelloForm extends ActionForm
{
public String name=”";

public HelloForm (){
super();
}

public String getName()
{
return name;
}

public void setName(String string)
{
name = string;
}

}

JSP
*****

<%@ taglib uri=”/WEB-INF/struts-html.tld” prefix=”html” %>
<%@ taglib uri=”/WEB-INF/struts-bean.tld” prefix=”bean” %>

<%@ page
language=”java”
contentType=”text/html; charset=ISO-8859-1″
pageEncoding=”ISO-8859-1″
%>

hello.jsp

action=”/test/hello”
type=”mj.eps.form.HelloForm”>

Place content here.

sudipkundu — Wed, 26 Mar 2008 08:29:27 +0000

1) documentDownload.jsp

<%@ taglib uri=”/WEB-INF/struts-html.tld” prefix=”html” %>
<%@ taglib uri=”/WEB-INF/struts-bean.tld” prefix=”bean” %>
<%@ taglib uri=”/WEB-INF/struts-logic.tld” prefix=”logic” %>
<%@ taglib uri=”/WEB-INF/pager-taglib.tld” prefix=”pg” %>
<%@ taglib uri=”/WEB-INF/c.tld” prefix=”c” %>

<%@ page
language=”java”
contentType=”text/html; charset=ISO-8859-1″
pageEncoding=”ISO-8859-1″ import=”com.mj.eps.framework.util.IConstant”
%>
type=”java.util.Vector” scope=”request” />

method=”POST”>

’,'<%=documentUploadObject.getPath()%>’)” />

Popup windows in struts

sudipkundu — Thu, 17 May 2007 05:20:30 +0000

Use Struts + Hibernate for a simple web app?

sudipkundu — Fri, 27 Apr 2007 12:12:32 +0000

My reason for Struts versus Spring is that it will be easier to find talent for maintenance of the system and Struts is already being used on other projects currently (where I work). I’m a consultant, so I want to leave behind code that is easy to maintain and/or find talent for (again, picked Struts for that reason).

As for Hibernate versus JDO, it appears this is a much discussed topic but Hibernate appears easier to use (to me, personally) and the fact that it is associated with EJB 3.0, gives me some warm-and-fuzzy that it’ll be around.

To summarize, my objectives are:
1. Keep things simple for quick development (less learning curve)

2. Use lightweight stuff (i.e. no EJBs, no heavy framework)

3. Make maintainability (ie. use industry standard stuff that you can find talent for easily such as standard J2EE, Struts, log4j, etc.)

Struts: get a property value from actionclass to jsp

sudipkundu — Tue, 10 Apr 2007 09:12:13 +0000

Set any value to the variable named ” refreshTimeInMiliSecs” in the action class and get its value in the JSP. The scope is “request” .

Case 2: show, how to get a value from the variable “username” which was stored in the session.

<%
String username=(String) session.getAttribute(“username”);
if(username==null) username=”";
%>

Struts submit button vs html link:

sudipkundu — Thu, 05 Apr 2007 06:39:07 +0000

In struts if u press submit button the whole form is get submitted to the corresponding action class. That is all the properties corresponds to the particular submit action in the jsp are transferred to respective getter/setter method of the action class.

submit action=”updateProfileSubmit” method=”submit” cssClass=”btn” value=’%{getText(“lbl.submit”)}’ onclick=”return checkUpdateProfile()” />

Try to do this:

Enter some text in the text box and press submit button. The action class will get the value entered in the text box. Using the submit button, u can easily do this.

Now if you want to do the same action using link, u can’t do that unless u use javascript.

javascript:paramSearch()” class=”bl” title=”Filter”>

function paramSearch(){

document.generatebean.action = “parameterSearch!parameterSearching.action”;

document.generatebean.submit();

}

Modal JWindow

sudipkundu — Wed, 07 Feb 2007 05:50:15 +0000

import java.awt.*;
import java.awt.event.*;

public class ModalWindowExample extends Frame {
  public ModalWindowExample() {
    super("ModalWindowExample Frame");

    add(new TextArea(), BorderLayout.CENTER);
    Button b = new Button("Show modal window");
    b.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        showModalWindow();
      }});
    add(b, BorderLayout.NORTH);
    pack();
    setLocation(100, 200);
    setVisible(true);
  }

  private void showModalWindow() {
    class HidingWindow extends Window {
	Button b = new Button("Close");

      public HidingWindow(Frame frame) {
        super(frame);
        setBackground(SystemColor.control);
  	setLayout(new BorderLayout());

       b.addActionListener(new ActionListener() {
      	public void actionPerformed(ActionEvent e) {
      		setVisible(false);
      	}});

        add(b, BorderLayout.NORTH);
      }

      public Insets getInsets() {
        return new Insets(2,2,2,2);
      }

      public void setVisible(boolean show) {
        super.setVisible(show);
        if (!show) {
          ModalWindowExample.this.setEnabled(true);
          ModalWindowExample.this.toFront();

        }else{
 	  toFront();
          b.requestFocus();
        }
      }

      public void paint(Graphics g) {
        Dimension size = getSize();
        Color c = g.getColor();
        g.setColor(SystemColor.control);
        g.fill3DRect(0,0, size.width, size.height, true);
        g.setColor(c);
        super.paint(g);
      }
    };

    final Window w = new HidingWindow(this);

    w.add(new TextArea(), BorderLayout.CENTER);

    w.pack();
    w.setLocation(400, 400);

    setEnabled(false);
    w.setVisible(true);
  }

  public static void main(String args[]) {
    Frame f = new ModalWindowExample();
    f.addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {System.exit(0);}
    });
  }
}

Annotation

sudipkundu — Thu, 10 Aug 2006 06:58:59 +0000

Annotation values are constants determined at compile time. They are read-only.

Annotations are meta-data about classes, methods and fields, not dynamic data.