1. 1 Copyright © 2004, Oracle. All rights reserved. Oracle Application Development Framework

2. Copyright © 2004, Oracle. All rights reserved. 1-2 Objectives After completing this lesson, you should be able to do the following: Describe the Java 2, Enterprise Edition (J2EE) platform Describe the benefits of framework-based application development Describe the purpose and benefits of Oracle ADF Describe the Model-View-Controller (MVC) architecture Describe the technologies used in each of the MVC layers

3. Copyright © 2004, Oracle. All rights reserved. 1-3 J2EE Platform Is a multitiered, distributed application model Supports component-based J2EE applications Business tier JSP/ Servlet Browser/ Application Business Services Web tierClient tierEIS tier Database ServerJ2EE ServerClient Machine Database

4. Copyright © 2004, Oracle. All rights reserved. 1-4

5. Copyright © 2004, Oracle. All rights reserved. 1-5 Benefits of the J2EE Platform “Write once, run anywhere” provides simplified component development. J2EE separates client requirements from business logic. J2EE provides multiple development and design scenarios: –Multitier –Web –Stand-alone client J2EE separates development tasks into specific skill areas.

6. Copyright © 2004, Oracle. All rights reserved. 1-6 J2EE Platform: Architecture Details JSP/ Servlet Browser Business Services Web container Client container EIS tierJ2EE Server Database Application Client APIs Business container Client Machine JMS JNDIRMI JDBC JTA JavaMail JAF

7. Copyright © 2004, Oracle. All rights reserved. 1-7 Building J2EE Applications Building J2EE applications can be complex. Development time can be extensive. Choosing and implementing appropriate design patterns can be overwhelming. “Do it yourself” applications often repeat existing application code. A large portion of “Do it yourself” code is dedicated to common tasks. The more code you write, the greater is the chance of errors. Using an existing application framework enables you to concentrate on your business needs.

8. Copyright © 2004, Oracle. All rights reserved. 1-8 What Is Framework-Based Application Development? A framework: Is a productivity layer for building applications Is a set of intelligent cooperating software components Is designed to be specialized for your business Handles the majority of common tasks with sensible behavior Enables easy customization of default behaviors Uses standard, proven techniques and design patterns

9. Copyright © 2004, Oracle. All rights reserved. 1-9 Understanding Framework-Based Application Development A framework provides base functionality: Standard behaviors Data access methods Transaction management You can augment or circumvent base functionality. Provides “hook points” to standard functions Your objects have only your code. Framework No messy code generation

10. Copyright © 2004, Oracle. All rights reserved. 1-10 Oracle Application Development Framework Reduces the complexity of J2EE development by providing visual and declarative development Increases development productivity –Less coding, more reuse –Focus on the application, not the “plumbing” Encourages J2EE best practices by implementing standard J2EE design patterns (MVC) Provides a flexible and extensible environment by allowing multiple technology choices and development styles

11. Copyright © 2004, Oracle. All rights reserved. 1-11 Visual and Declarative Development Visual –WYSIWYG editors –UML modelers –Structure pane Declarative –Structure pane –Property Inspector Code view/design view synchronization –No separate generation step—always synchronized –Underlying code always accessible

12. Copyright © 2004, Oracle. All rights reserved. 1-12 Design Patterns Design patterns: –Are proven solutions to specific problems –Are a means to an end, not the end itself –Address programming tasks, not business problems –Are reusable –Provide a framework for re-creatable results The MVC architecture is an example of a design pattern.

13. Copyright © 2004, Oracle. All rights reserved. 1-13 Model-View-Controller Architecture MVC provides logical separation of an application. Browser/ Application Web tier Client tier EIS tier Database View Controller Model Business tier Business Services

14. Copyright © 2004, Oracle. All rights reserved. 1-14 MVC Structure View Renders the UI Requests data from the Model Sends “Events” to the Model Allows the Controller to select the next View Model Stores the application state Responds to data requests Encapsulates business logic DisplaySubmit page Request data Handles routing to the correct page Maps UI data changes to the Model Data and transactions Controller

15. Copyright © 2004, Oracle. All rights reserved. 1-15 What Is the Model? It is a wrapper and abstraction for business services: –Handles data events from the Controller –Feeds data to the View It manages and presents data from different Business Service types in a common way. View Controller Model

16. Copyright © 2004, Oracle. All rights reserved. 1-16 The Model Layer Business Services Model TopLink Mapping ADF Bindings ADF Data Control Web Services ADF Application Module Java Classes EJB Session Beans TopLink Queries ADF View Object Java Classes EJB Finders ADF Entity Object EJB Entity Beans JDBC

17. Copyright © 2004, Oracle. All rights reserved. 1-17 Components of the Model Layer Bindings: –Metadata that describes how the UI components on a page use the values and actions provided by the Business Service Data controls: –Metadata that describes the data model returned by the Business Service The metadata has the same format for all business services. ADF Bindings ADF Data Control

18. Copyright © 2004, Oracle. All rights reserved. 1-18 What Is the Controller? On a Web page, everything significant happens on submit or a link. A Controller intercepts a request and dispatches it to the correct page. The source page does not have to know how to handle an event or where to go next. The handling code does not need to know what page to display in response. The Controller separates the Model and the View. The Controller manages the flow of a Web application.

19. Copyright © 2004, Oracle. All rights reserved. 1-19 Struts in JDeveloper JDeveloper uses Apache Struts as a Controller. It is popular among J2EE developers. It has been around since 2000. It is designed to handle views based on HTTP technology.

20. Copyright © 2004, Oracle. All rights reserved. 1-20 Controller: Summary Controllers are key to MVC separation and to promote code and layer reuse. Apache Struts is the de facto standard for Web application controllers. Oracle JDeveloper 10g supports Struts as a controller.

21. Copyright © 2004, Oracle. All rights reserved. 1-21 What Is the View? The MVC View is the UI of the application. It is what the end user sees and interacts with. View Controller Model

22. Copyright © 2004, Oracle. All rights reserved. 1-22 View Concept A View does not contain application code; it contains code to represent the UI and pass events to the Controller. Views are interchangeable without rewriting controller or model logic. A single application can have different Views that are compatible with different types of devices (HTML browser, handheld devices, and so on).

23. Copyright © 2004, Oracle. All rights reserved. 1-23 View Technologies in Oracle JDeveloper 10g JavaServer Pages (JSP) UIX ADF JClient Creating databound clients is the same in JDeveloper for any of these supported client technologies.

24. Copyright © 2004, Oracle. All rights reserved. 1-24 View: Summary Views contain only display code. Views do not contain application logic. Views do not contain navigation logic. Views are independent of the Controller and the Model.

25. Copyright © 2004, Oracle. All rights reserved. 1-25 ADF Technology Stack Web Services EJB Session Beans JavaBeans/ Other JSPJSF Struts Swing/ ADF JClient ADF UIX ADF Business Components ADF Model View Controller Model Business Services

26. Copyright © 2004, Oracle. All rights reserved. 1-26 ADF: Summary Productive end-to-end development –Model-View-Controller –Visual –Declarative Standard J2EE framework –Implements J2EE best practices –Uses the latest standards –Provides architecture choices –Is built on the MVC design pattern

27. Copyright © 2004, Oracle. All rights reserved. 1-27 Summary In this lesson, you should have learned how to: Identify the benefits of framework-based application development Describe the Java 2, Enterprise Edition (J2EE) platform Define the components of the Model-View- Controller architecture Describe the benefits of Oracle Application Development Framework (ADF) Describe the technologies used in each of the MVC layers

28. Copyright © 2004, Oracle. All rights reserved. 1-28