26-07-2014, 04:50 PM
SYSTEM REQUIREMENT
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SOFTWARE SPECIFICATION
Java Server Pages or JSP for short is Sun's solution for developing dynamic web sites. JSP provide excellent server side scripting support for creating database driven web applications. JSP enable the developers to directly insert java code into jsp file, this makes the development process very simple and its maintenance also becomes very easy. JSP pages are efficient, it loads into the web servers memory on receiving the request very first time and the subsequent calls are served within a very short period of time.
In today's environment most web sites servers dynamic pages based on user request. Database is very convenient way to store the data of users and other things. JDBC provide excellent database connectivity in heterogeneous database environment. Using JSP and JDBC its very easy to develop database driven web application.
Java is known for its characteristic of "write once, run anywhere." JSP pages are platform independent. Your port your .jsp pages to any platform.
Evolution of Web Applications
Over the last few years, web server applications have evolved from static to dynamic applications. This evolution became necessary due to some deficiencies in earlier web site design. For example, to put more of business processes on the web, whether in business-to-consumer (B2C) or business-to-business (B2B) markets, conventional web site design technologies are not enough. The main issues, every developer faces when developing web applications, are:
1. Scalability - a successful site will have more users and as the number of users is increasing fastly, the web applications have to scale correspondingly.
2. Integration of data and business logic - the web is just another way to conduct business, and so it should be able to use the same middle-tier and data-access code.
3. Manageability - web sites just keep getting bigger and we need some viable mechanism to manage the ever-increasing content and its interaction with business systems.
4. Personalization - adding a personal touch to the web page becomes an essential factor to keep our customer coming back again. Knowing their preferences, allowing them to configure the information they view, remembering their past transactions or frequent search keywords are all important in providing feedback and interaction from what is otherwise a fairly one-sided conversation.
Apart from these general needs for a business-oriented web site, the necessity for new technologies to create robust, dynamic and compact server-side web applications has been realized. The main characteristics of today's dynamic web server applications are as follows:
1. Serve HTML and XML, and stream data to the web client
2. Separate presentation, logic and data
3. Interface to databases, other Java applications, CORBA, directory and mail services
4. Make use of application server middleware to provide transactional support.
5. Track client sessions
The Dispatcher Approach
Client Application Development
Client applications are the closest to a traditional style of application in Windows-based programming. These are the types of applications that display windows or forms on the desktop, enabling a user to perform a task. Client applications include applications such as word processors and spreadsheets, as well as custom business applications such as data-entry tools, reporting tools, and so on. Client applications usually employ windows, menus, buttons, and other GUI elements, and they likely access local resources such as the file system and peripherals such as printers.
In this approach, a Servlet or JSP acts as a mediator or controller, delegating requests to JSP pages and JavaBeans. There are three different architectures. They are mediator-view, mediator-composite view and service to workers.
In an N-tier application, the server side of the architecture is broken up into multiple tiers. In this case, the application is composed of multiple tiers, where the middle tier, the JSP, interacts with the back end resources via another object or EJBs component. The Enterprise JavaBeans server and the EJB provide managed access to resources, support transactions and access to underlying security mechanisms, thus addressing the resource sharing and performance issues of the 2-tier approach.
The first step in N-tiered application design should be identifying the correct objects and their interaction and the second step is identifying the JSPs or Servlets. These are divided into two categories.
Front end JSPs or Servlets manage application flow and business logic evaluation. They act as a point to intercept the HTTP requests coming from the users. They provide a single entry point to an application, simplifying security management and making application state easier to maintain.
Presentation JSPs or Servlets generate HTML or XML with their main purpose in life being presentation of dynamic content. They contain only presentation and rendering logic.
These categories resemble to the Modal-View design pattern, where the front-end components is the model and the presentation component the view. In this approach, JSPs are used to generate the presentation layer and either JSPs or Servlets to perform process-intensive tasks. The front-end component acts as the controller and is in charge of the request processing and the creation of any beans or objects used by the presentation JSP, as well as deciding, depending on the user's actions, which JSP to forward this request to. There is no processing logic within the presentation JSP itself and it simply responsible for retrieving any objects or beans that may have been previously created by the Servlet and extracting the dynamic content for insertion within static templates.
Basic Swing concepts: events and listeners
In our introduction to Swing, we saw a very basic user interface program that popped up a blank window. But apart from popping up the window, it didn't really "do" very much. To start making our user interface "do" things, we have to start thinking in terms of events.
In any GUI-based program1, a lot of the functionality comes from responding to events: mouse clicks, button clicks, key presses etc. So the first challenge with GUI programming is often