| Oracle® Application Development Framework Developer's Guide For Forms/4GL Developers 10g (10.1.3.1.0) Part Number B25947-01 |
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| Oracle® Application Development Framework Developer's Guide For Forms/4GL Developers 10g (10.1.3.1.0) Part Number B25947-01 |
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View PDF |
ADF has additional functionality that can greatly improve your development productivity. These features include:
Section 1.4.1, "Comprehensive JDeveloper Design-Time Support"
Section 1.4.2, "Sophisticated AJAX-Style Web Pages Without Coding"
Section 1.4.4, "Generation of Complete Web Tier Using Oracle JHeadstart"
The Studio Edition of JDeveloper includes all of the following facilities that simplify development of enterprise solutions using Oracle ADF and JavaServer Faces:
Facilities for Business Services Development
Business Components wizards and editors
Quickly create and modify the components that comprise your business services using productive wizards and editors. Reverse-engineer components from existing tables. Synchronize your components with changes that you (or the DBA) have made to the underlying database schema.
Business Components Browser
Interactively test your business service's data model even before you build a user interface. The Business Components Browser can also help isolate where problems in your application occur, as it runs your data model without running your user interface.
Business Components Diagrammer
Visualize, create, or modify your business service and business domain layer components using UML diagrams. Publish the diagrams to numerous formats for reference or inclusion in system documentation.
Facilities for Declarative Data Binding
Data control wizards
ADF application modules are automatically exposed as data controls. Should your needs call for working with web services, XML or CSV data from a URL, JavaBeans, or EJB session beans, handy data control wizards guide you step by step.
Data Control Palette
Visualize all application modules and other business services and drag their data collections, properties, methods, method parameters, and method results to create appropriate bound user interface elements. Easily create read-only and editable forms, tables, master/detail displays, and individual bound UI components including single and multiselect lists, checkboxes, radio groups, and so on. Creating search forms, data creation pages, and parameter forms for invoking methods is just as easy. If your process involves collaboration with page designers in another team, you can drop attributes onto existing components on the page to bind them after the fact. In addition to the UI components created, appropriate declarative bindings are created and configured for you in the page definition file with robust undo support so that you can modify your user interface with confidence that your bindings and UI components will stay in sync.
Page Definition Editor
Visualize page definition metadata in the Structure window and configure declarative binding properties using the appropriate editor or the Property Inspector. Create new bindings by inserting them into the structure where desired. Edit binding metadata with context-sensitive, XML schema-driven assistance on the structure and valid values.
Service method invocation
Configure business service method invocations with EL expression-based parameter passing. You can have methods invoked by the click of a command component like a link or button, or configure your page definition to automatically invoke the method at an appropriate phase of the JSF lifecycle
Page lifecycle control
Declaratively configure an iterator binding to refresh its data during a specific JSF lifecycle phase, and optionally provide a conditional EL expression for finer control over when that refresh is desired. You have the same control over when any automatic method invocation should invoke its method as well.
Centralized error reporting
Customize the error reporting approach for your application in a single point instead of on each page.
Facilities for Visual Web Page Design
Visual Web Page Designer
Design your web pages visually using the visual web page designer. The designer is integrated with the Data Control Palette to support both drag and drop creation of user interfaces, and UI-first page design with subsequent data binding applied to an initial page mockup. The visual editor supports both JavaServer Faces and traditional JSP development.
Page Flow Diagrammer
Design your web page navigation visually using the visual page flow diagram. The diagrammer supports both JavaServer Faces as well as Apache Struts.
Facilities for Visual Design for Desktop-Fidelity UI's with Swing
Visual Form Designer
JDeveloper fully supports developing desktop-fidelity user interfaces using Forms and Panels that use the standard Swing controls provided as part of Java itself. All of the Oracle ADF declarative data binding and ADF Business Components facilities work to make building either client/server or three-tier Swing applications easy.
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Note: This edition of the developer's guide focuses exclusively on Web development with JSF. The development of desktop-fidelity user interfaces using Oracle ADF and ADF Swing will be covered in a separate, follow-on developer's guide dedicated to that subject. |
The JSF reference implementation provides a bare-bones set of basic UI components which includes basic HTML input field types and a simple table display, but these won't take you very far when building real-world applications. The ADF Model layer implements several features that work hand-in-hand with the more sophisticated UI components in the Oracle ADF Faces library to make quick work of the rich functionality your end users crave, including:
Declarative partial page refreshing for interactive UIs
For any UI component in your pages, you can indicate declaratively which other components should trigger its being "repainted" with fresh data without causing the entire browser page to refresh. This type of more interactive web experience is known popularly as "Web 2.0" or "AJAX"-style pages.
Sophisticated table model
Tables are a critical element of enterprise application UIs. By default, JSF doesn't support paging or sorting in tables. The ADF Faces table and the ADF Model table binding cooperate to display pageable, editable or read-only, tables with sorting on any column.
Key-based current selection tracking
One of the most common tasks of web user interfaces is presenting lists of information and allowing the user to scroll through them or to select one or more entries in the list. The ADF Model iterator binding simplifies tracking the selected row in a robust way, using row keys instead of relying on positional indicators that can change when data is refreshed. In concert with the ADF Faces table and multiselection components, it's easy to work with single or multiple selections, and build screens that navigate master/detail information.
Declarative hierarchical tree components and grids
Much of the information in enterprise applications is hierarchical, but JSF doesn't support displaying or manipulating hierarchical data out of the box. The ADF Model layer provides hierarchical bindings that you can configure declaratively and use with the ADF Faces tree or hierarchical grid components to implement interactive user interfaces that present data in the most intuitive way to your users.
Flexible models for common UI components
Even simple components like the checkbox can be improved upon. By default, JSF supports binding a checkbox only to boolean properties. ADF Model adds the ability to map the checkbox to any combination of true or valid values your data may present. List components are another area where ADF Model excels. The valid values for the list can come from any data collection in a data control and the list can perform updates or be used for row navigation, depending on your needs. The ADF Model list binding also makes null-handling easy by optionally adding a translatable "<No Selection>" choice to the list.
Oracle ADF improves the reuse of several aspects of application functionality by allowing you to associate layered metadata with either your ADF Business Components or, for other data control types, the data control structure definitions that describe the data collections. These can then be reused by any page presenting their information. Examples of this functionality are:
Easily localizable prompts, tooltips, and format masks
JSF supports a simple mechanism to reference translatable strings in resource bundles, but it has no knowledge of what the strings are used for and no way to associate the strings with specific business domain objects. ADF Business Components improves on this by allowing your JSF pages to reference translatable prompts, tooltips, and format masks that you can associate with any attribute of any entity object or view object component. In this way, data is presented in a consistent, locale-sensitive way on every page where it appears.
Declarative validation
JSF supports validators that can be associated with a UI component. These offer the ability to perform basic syntactic checks on the data value. However, JSF offers no mechanism to simplify enterprise, database-centric validation nor to easily validate the same business domain data in a consistent way on every screen where it's used. ADF Business Components improves on this by allowing you to associate an extensible set of validator objects with your entity objects, and supplement that with validation code you write in event handlers as shown in Section 1.3.4, "Simple, Event-Driven Approach to Add Custom Logic". In this way, the validations are enforced consistently, regardless of which page the user employs to enter or modify the object's data.
Declarative security
JSF has no mechanism for integrating authorization information with UI components. With ADF Business Components, you can associate user or role authorization information with each attribute in an entity object so that your JSF pages can easily display data only to users authorized to see it.
As you'll learn throughout the rest of this guide, Oracle JDeveloper 10g and Oracle ADF give you a productive, visual environment for building richly functional, database-centric J2EE applications with a maximally declarative development experience. However, if you are used to working with tools like Oracle Designer that offer complete user interface generation based on a higher-level application structure definition, you may be looking for a similar facility for your J2EE development. If so, then the Oracle JHeadstart 10g application generator may be of interest to you. It is an additional extension for JDeveloper that stands on the shoulders of Oracle ADF's built-in features to offer complete web-tier generation for your application modules. Starting with the data model you've designed for your ADF business service, you use the integrated editors JHeadstart adds to the JDeveloper environment to iteratively refine a higher-level application structure definition. This controls the functionality and organization of the view objects' information in your generated web user interface. By checking boxes and choosing various options from dropdown lists, you describe a logical hierarchy of pages that can include multiple styles of search regions, List of Values (LOVs) with validation, shuttle controls, nested tables, and other features. These declarative choices use terminology familiar to Oracle Forms and Designer users, further simplifying web development. Based on the application structure definition, you generate a complete web application that automatically implements the best practices described in this guide, easily leveraging the most sophisticated features that Oracle ADF and JSF have to offer.
Whenever you run the JHeadstart application generator, rather than generating code, it creates (or regenerates) all of the declarative view and controller layer artifacts of your ADF-based web application. These use the ADF Model layer and work with your ADF application module as their business service. The generated files are the same kinds you produce when using JDeveloper's built-in visual editors. The key difference is that JHeadstart creates them in bulk based on a higher-level definition that you can iteratively refine until the generated pages match your end-users' requirements as closely as possible. The generated files include:
JSF Pages with data-bound ADF Faces UI components
ADF Model page definition XML files describing each page's data bindings
JSF navigation rules to handle page flow
Resource files containing localizable UI strings
Once you've generated a maximal amount of your application's web user interface, you can spend your time using JDeveloper's productive environment to tailor the results or to concentrate your effort on additional showcase pages that need special attention. Once you've modified a generated page, you can adjust a setting to avoid regenerating that page on subsequent runs of the application generator. Of course, since both the generated pages and your custom designed ones leverage the same ADF Faces UI components, all of your pages automatically inherit a consistent look and feel. For more information on how to get a fully-functional trial of JHeadstart for evaluation, including details on pricing, support, and additional services, see http://otn.oracle.com/consulting/9iServices/JHeadstart.html.
