object oriented analysis and design 1 chapter 8 - web application system design modeling web...

Object Oriented Analysis and Design 1

Chapter 8 - Web Application System Design Modeling Web Application using UML Application Server Web Application Design

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Modeling Web Applicationusing UML

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8.1 - Modeling Web Application using UML Modeling Web Pages Modeling EJB

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Modeling Web Pages For web pages, the stereotypes indicate that the

class is an abstraction of the logical behavior of a web page on either the client or the server. The two abstractions are related to each other with a directional relationship between the two. This association is stereotyped as «build», since it can be said that a server page builds a client page .

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Modeling Web Pages

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Modeling Web Pages

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Modeling Web Pages

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Modeling Web Pages

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Modeling Web Pages

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Modeling EJB Modeling EJB as a subsystem Two approach:

Standard UML-Java Mapping Sun JSR-000026 UML/EJB Mapping

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Modeling EJB as a subsystem

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Modeling EJB as a subsystemICustomerMgt  => CustomerHome (home interface) 

Icustomer    => Customer (remote interface)

<<subsystem proxy>>Customer   =>CustomerEJB (bean class)

validateCustomer() => findUser() (in home interface)

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Modeling EJB as a subsystem

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Modeling EJB as a subsystem

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Modeling EJB as a subsystem

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Modeling EJB as a subsystem

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Standard UML-Java Mapping

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Sun JSR-000026 UML/EJB Mapping

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Application Server

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8.2 - Application Server Application Servers J2EE Application Servers Web Server and Application Server

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Application Servers In the beginning, there was darkness and

cold. Then, …

Centralized, non-distributed

terminals

mainframe

terminals

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Application Servers The In the 90' s, systems should be client-

server

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Application ServersToday, enterprise applications use

the multi-tier model

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Application Servers " The Multi- tier applications" have several

independent components An application server provides the

infrastructure and services to run such applications

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Application Servers Application server products can be separated

into 3 categories: J2EE-based solutions Non-J2EE solutions (PHP, ColdFusion, Perl, etc.) And the Microsoft solution (ASP/COM and

now .NET with ASP.NET, VB.NET, C#, etc.)

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J2EE Application Servers Major J2EE products:

BEA WebLogic IBM WebSphere Sun iPlanet Application Server Oracle 9iAS HP/Bluestone Total-e-Server Borland AppServer Jboss (free open source)

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Web Server and Application Server

Web Server

(HTTP Server)

App Server 1

App Server 2

Internet Browser

HTTP(S)

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Web Application Design

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8.3 - Web Application Design Application Layer Business Layer J2EE Multi-tier Model J2EE Application Scenarios Main Technologies Examples Case Study –Online Bank

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Application Layer

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Business Layer

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J2EE Multi-tier Model

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J2EE Application Scenarios Multi-tier typical application

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J2EE Application Scenarios Stand-alone client

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J2EE Application Scenarios Web-centric application

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J2EE Application Scenarios Business-to-business

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Main technologies JavaServer Pages (JSP) Servlet Enterprise JavaBeans (EJB)

JSPs, servlets and EJBs are application components

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JSP Used for web pages with dynamic content Processes HTTP requests (non-blocking call-and-

return) Accepts HTML tags, special JSP tags, and

scriptlets of Java code Separates static content from presentation logic Can be created by web designer using HTML tools

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Servlet Used for web pages with dynamic content Processes HTTP requests (non-blocking call-

and-return) Written in Java; uses print statements to render

HTML Loaded into memory once and then called many

times Provides APIs for session management

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EJB EJBs are distributed components used to

implement business logic (no UI) Developer concentrates on business logic Availability, scalability, security,

interoperability and integrability handled by the J2EE server

Client of EJBs can be JSPs, servlets, other EJBs and external aplications

Clients see interfaces

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EJB – The Big Picture

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EJB at runtime

Client can be local or remote

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EJB at runtime

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Types of EJB

EJB Taxonomy

Sta te ful

Sta te le ss

Se ssionBea n

BMP

C MP

EntityBea n M essa geDrivenBea n

Ente rp riseBea n

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Session Bean Stateful session bean:

Retains conversational state (data) on behalf of an individual client

If state changed during this invocation, the same state will be available upon the following invocation

Example: shopping cart

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Session Bean Stateless session bean:

Contains no user-specific data Business process that provides a generic

service Container can pool stateless beans Example: shopping catalog

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Entity Bean Represents business data stored in a database ?

persistent object Underlying data is normally one row of a table A primary key uniquely identifies each bean

instance Allows shared access from multiple clients The Can live past the duration of client' s

session Example: shopping order

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Entity Bean Bean-managed persistence (BMP): bean

developer writes JDBC code to access the database; allows better control for the developer

Container-managed persistence (CMP): container generates all JDBC code to access the database; developer has less code to write, but also less control

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Message-Driven Bean Message consumer for a JMS queue or

topic Benefits from EJB container services that

are not available to standard JMS consumers

Has no home or remote interface Example: Order processing – stock info

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Examples JSP example Servlet example EJB example

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JSP example

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JSP example<%@ page import="hello.Greeting" %>

<jsp:useBean id="mybean" scope="page" class="hello.Greeting"/>

<jsp:setProperty name="mybean" property="*" />

<html>

<head><title>Hello, User</title></head>

<body bgcolor="#ffffff" background="background.gif">

<%@ include file="dukebanner.html" %>

<table border="0" width="700">

<tr>

<td width="150"> &nbsp; </td>

<td width="550">

<h1>My name is Duke. What's yours?</h1>

</td>

</tr>

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JSP example<tr> <td width="150" &nbsp; </td> <td width="550"><form method="get"><input type="text" name="username" size="25"> <br><input type="submit" value="Submit"><input type="reset" value="Reset"></td> </tr></form> </table><% if (request.getParameter("username") != null) {%><%@ include file="response.jsp" %><% }%></body></html>

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Servlet examplepublic class HelloWorldServlet extends HttpServlet {

public void service(HttpServletRequest req, HttpServletResponse res) throws IOException {

res.setContentType("text/html"); PrintWriter out = res.getWriter(); out.println("<html><head><title>Hello World Servlet</title></head>"); out.println("<body><h1>Hello World!</h1></body></html>"); }

}

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EJB Example// Shopping Cart example

// Home interface public interface CartHome extends EJBHome {

Cart create(String person) throws RemoteException, CreateException;

Cart create(String person, String id) throws RemoteException, CreateException;}

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EJB Example// Remote interfacepublic interface Cart extends EJBObject {

public void addBook(String title) throws RemoteException;

public void removeBook(String title) throws BookException, RemoteException;

public Vector getContents() throws RemoteException;}

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EJB Example// Enterprise bean class

public class CartEJB implements SessionBean {

String customerName, customerId;

Vector contents;

private SessionContext sc;

public void ejbCreate(String person) throws CreateException {

if (person == null) {

throw new CreateException("Null person not allowed.");

}

else {

customerName = person;

}

customerId = "0";

contents = new Vector();

}

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EJB Example public void ejbCreate(String person, String id) throws CreateException { if (person == null) { throw new CreateException("Null person not allowed."); } else { customerName = person; } IdVerifier idChecker = new IdVerifier(); if (idChecker.validate(id)) { customerId = id; } else { throw new CreateException("Invalid id: " + id); } contents = new Vector(); }

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EJB Example public void addBook(String title) { contents. addElement(title); }

public void removeBook(String title) throws BookException { boolean result = contents.removeElement(title); if (result == false) { throw new BookException(title + " not in cart."); } }

public Vector getContents() { return contents; }

. . .}

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EJB Example// EJB client (stand-alone application)public class CartClient { public static void main(String[] args) { try { CartHome home = (CartHome)initial.lookup("MyCart"); Cart shoppingCart = home.create("Duke DeEarl", "123"); shoppingCart.addBook("The Martian Chronicles"); shoppingCart.addBook("2001 A Space Odyssey"); shoppingCart.remove(); } catch (BookException ex) { System.err.println("Caught a BookException: " + ex.getMessage()); } catch (Exception ex) { System.err.println("Caught an unexpected exception!"); } }}

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Case Study – Online Bank

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Case Study – Online Bank

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Case Study – Online Bank

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Case Study – Online Bank

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Case Study – Online Bank

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Case Study – Online Bank

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Case Study – Online Bank

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Case Study – Online Bank

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Case Study – Online Bank

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Case Study – Online Bank

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Case Study – Online Bank

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Case Study – Online Bank

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Case Study – Online Bank