Gartner Day

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Workshop Agenda

• Understanding the Application Architecture
• Designing and Implementing the Business Tier with
  Enterprise JavaBeans
• Designing the Web Tier Using MVC and Struts
• Securing Access to the Application
• Tuning and Debugging J2EE Applications

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Who Are We?

• Person AProduct ManagementOracle Application
  Server 10g
• Person BProduct Management Oracle JDeveloper
  10g

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Understanding the Application Architecture Session
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Kevin WongSenior Product Manager Oracle
Corporation
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Agenda

• An example application
• J2EE application tiers
• J2EE architecture choices

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An Example Application

• A common problem - FAQ
• A system could reduce effort and produce better
  results
• More accurate information
• More timely updates
• Base application on requirements from key players

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Application Requirements

• Must be accessible and flexible
• Browser access encourages use
• Data gathering
• Domain expertise is split across different areas
• Areas should sub-divided
• Answers may be applicable across different areas
• Extensible and flexible
• Early requirement to produce reports for
  publishing
• Future requirements for bulk loading, Web
  services

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Use Cases

• What will users do?

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Domain Objects

• What are the things we need to work with?

Area a specific problem space
Topic a category of an area
QA the question and answer
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From Requirements to Design

• From the use case
• Page flows for Web interactions
• Interactions with domain model
• From the domain model
• Object model for business objects and tasks

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D E M O N S T R A T I O N
The FAQ Application
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Agenda

• An example application
• J2EE application tiers
• J2EE architecture choices

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Application Layers

• J2EE helps developers build layered applications,
  each providing different services.

Presentation
Control
Business Logic
Persistent Objects
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Application Layers Mapped to J2EE Tiers and
Technology

• Analyze how the requirements fall into the layers
  and map to technology

J2EE Technology
Application Layer
J2EE Tier
HTML, JSP
Presentation
Web Tier
Servlets
Control
Web Tier
Java Objects, Session Beans
Business Logic
Business Tier
Java Objects, Entity Beans
Persistent Objects
Business Tier
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Mapping to Implementation Technology

• The FAQ Application implementation

Application Layer
J2EE Tier
FAQ Implementation
Page Flow JSP Struts
Session Facade
Business Logic
Business Tier
EJB Entity Beans
Persistent Objects
Business Tier
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Agenda

• An example application
• J2EE application tiers
• J2EE architecture choices

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Web Application / JDBC

• Simplest of architectures
• Combines presentation and business logic in one
  tier
• Business logic separated into separate classes

Web Container
JSP Servlet UI
Business Logic JDBC
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Web Application / JDBC

• Pros
• Simple to build
• Simple to package and deploy
• Low overhead from container
• Relatively easy to test
• Cons
• Needs discipline to keep UI and logic separate
• No container transaction support
• Must code all database calls

Web Container
JSP Servlet UI
Business Logic JDBC
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Web Application / Local EJB

• Next generation J2EE architecture
• Presentation logic with JSP and Servlets in Web
  container
• Separates business logic into EJB tier exposed
  via local interfaces

Web EJB Container
JSP Servlet UI
local
Session Bean - Logic Entity Bean - Persistence
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Web Application / Local EJB

• Pros
• Separation of business logic
• Entity beans for persistence
• No serialization or network calls
• Concurrency managed
• Can convert to remote interface and Web service
  endpoint if required
• Cons
• Uses EJB infrastructure
• Harder to test business logic behind local
  interfaces

Web EJB Container
JSP Servlet UI
local
Session Bean - Logic Entity Bean - Persistence
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Web Application / Remote EJB
Web Container

• The theoretical J2EE architecture
• EJB tier exposed via remote interfaces
• EJB tier can run on separate server

JSP Servlet UI
Web Container
remote
EJB Container
Session Bean - Logic Entity Bean - Persistence
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Web Application / Remote EJB
Web Container

• Pros
• Most flexible architecture
• Can separate EJB container to different server
• Multi client enabled
• Can be exposed as Web service endpoint
• Cons
• Slower performance, remote network calls and
  serialization
• Can be difficult to configure and debug

JSP Servlet UI
Web Container
remote
EJB Container
Session Bean - Logic Entity Bean - Persistence
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Application Architectures

• The architecture choice you make heavily
  influences how you build the application
• Using EJBs allows you to more easily move between
  local and remote architectures
• If in doubt, design for flexibility and monitor
  performance

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Summary

• Application design should be driven from
  requirements
• J2EE provides support for layering of application
• J2EE supports a wide variety of deployment
  architectures

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Learn Oracle From Oracle

• Instructor led training
• Self-Study
• Online learning

• Oracle Certification
• Oracle iLearning
• Oracle Tutor

oracle.com/education Recommended Class
Oracle9i Build J2EE Applications
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