Simplify Web Applications with Stripes

Stripes is a JDK 1.5 based framework for building web

applications. What makes this framework stand apart from the rest of the java

based frameworks is the fact that it does not require extensive configuration

other than adding entries for a 'Dispatcher Servlet' and filters in the

deployment descriptor. The latest release (Stripes 1.3) also provides

'Spring' and '



AJAX



' integration. That way it can truly help with building low bandwidth web

applications. The good thing about Stripes is that it is simple and hence easy

to use. It uses JDK1.5, Servlet 2.4 and JSP 2.0. All you need to run a Stripes

based application is a Servlet container that supports these versions. In this

article we provide a small sample application that displays a greeting message

to describe how to get started with using this framework for your web

application.

How it works



Stripes' presentation layer consists of web pages that can be defined

using JSP. These JSP pages can import the Stripes tag-library using the

following declaration in the JSP file:

The action elements in these JSP pages forward the request

to 'ActionBean'. This is the heart of all properties of the action element

and processing logic in a Stripes application. This is a major difference with

other lightweight component based frameworks where the same class or object at

runtime handles both these tasks. Moreover you do not need any external

configuration for defining the 'ActionBean' implementation in an application

or for binding the JSP page request to the 'ActionBean'. This information is

defined in the 'ActionBean' itself.

Setting it up



You need to download the Stripes framework package from the URL

http://stripes.mc4j.org/confluence/display/stripes/Download and unzip it to a

location of your choice on the hard drive. Thereafter you need to add the path

for all the 'jars' that you find in the 'lib' directory of your Stripes

installation to the 'classpath' variable.

Configuring a Stripes application



Configuration is minimal in Stripes; we first start by configuring the

'web.xml' file to define a 'Stripes Filter' and a 'Stripes

Dispatcher' Servlet. These entries will be as follows:

StripesFilter





net.sourceforge.stripes.controller.StripesFilter

StripesFilter


*.jsp

REQUEST

StripesFilter



StripesDispatcher

REQUEST

Stripes Dispatcher
Servlet




StripesDispatcher





net.sourceforge.stripes.controller.DispatcherServlet

1

StripesDispatcher


/dispatcher

StripesDispatcher


/action/*

StripesDispatcher


*.action

As you can see from the deployment descriptor listed above

you do not need to configure any thing else except the Stripes Filter and the

Servlet mappings. Next you need to define 'log4j', 'commons-logging' and

a 'StripesResources' properties file. The first two contain standard entries

for a web application whereas a StripesResources file defines error messages for

defined validations and the file has to be available in at the folder specified

by CLASSPATH. Also setup a context path entry 'Stripes-PCQ' in

'context.xml'

Building the JSP Page



Our application's JSP page displays a form asking for entering name, age

and sex. After that, it prints a display message with the values provided. The

JSP page is as follows:

 

Stripes Demo PCQ

The 'ActionBean' Implementer



The ActionBean we described earlier is an interface that implemented for

application specific goals in Stripes. Here we implement this interface
overriding two of its methods-'getActionBeanContext()' and 'setActionBeanContext()'.

The ActionBean implementation is as follows:

package com.pcq.stripes;



import net.sourceforge.stripes.action.DefaultHandler;


import net.sourceforge.stripes.action.Resolution;


import net.sourceforge.stripes.action.ForwardResolution;


import net.sourceforge.stripes.action.ActionBean;


import net.sourceforge.stripes.action.ActionBeanContext;


public class HelloWorldBean implements ActionBean {


private ActionBeanContext context;


private String usrName;


private int age;


private String sex;


private String greet;


public ActionBeanContext getContext() { return context; }


public void setContext(ActionBeanContext context) {
this.context = context; }



public String getusrName() { return usrName; }


public void setusrName(String usrName) { this.usrName =
usrName; }



public int getAge() { return age; }


public void setAge(int age) { this.age = age; }

public String getSex() { return sex; }







public void setSex(String sex) { this.sex = sex; }

public String getGreet(){



return greet;







}

public void setGreet(String greet){



this.greet = greet;







}

public void setGreet(String name, String

sex){



if(sex.equals("Male") ||
sex.equals("male") || sex.equals("MALE"))



greet =
"Hello Mr. "+name;







else if(sex.equals("Female")
|| sex.equals("female") || sex.equals("FEMALE"))







greet =
"Hello Ms. "+name;







else greet = "Hello "+name;







}

@DefaultHandler







public Resolution showGreet() {

setGreet(this.getusrName(),this.getSex());







return new ForwardResolution("/Stripes-PCQ/index.jsp");







}

These methods provide the ActionBean with access to the

ActionBeanContext, which provides access to the HttpServlet Request and

HttpServletResponse, as well as other information about the current request.

Most of the code is pretty obvious except for a '@DefaultHandler'.

This annotation describes application behavior if it cannot

find out what button the user hit (in case you press enter key!), which in our

case is to do the same, i.e. print the message. The Resolution Stripes will

identify the showGreet() method as a 'handler' method. When a request comes

to the HelloWorldBean, and the user hits a submit button with name (not value)

"showGreet", this method will be invoked. Just like with the URL

above, the name of the event that a method handles can be overridden using the @HandlesEvent

annotation.

With all the files defined you need to build the WAR

archive

using any tool and simply deploy it to a Servlet container

or application server of your choice. The deployment procedure would vary from

server to server. Access the following URL to view the JSP page:

http://localhost:8080/Stripes-PCQ/index.jsp

In conclusion



The framework is pretty easy to use and setup. It has some good design

features such as the 'ActionBean' we described and is extensible to



AJAX



. It can surely be a one-stop shop for developers looking for resource friendly

web applications that can be coded and deployed without much fuss.

Anadi Misra