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Download and run the Order Demo application to illustrate concepts presented here (and in other Middleware Developer Guides).
It features an impressive StoreFront built using a web technology stack, including ADF Faces Rich Client Components and JavaServer Faces Pages; screenshots and code examples from its StoreFront module are used here to show how Oracle ADF can be applied within applications using a web technology stack. Click here for further details regarding its StoreFront Module in Order Demo App.
Oracle ADF Architecture
Following community best practices, web applications developed using a web technology stack achieve clean separation of business logic from page navigation and user interface by adopting an MVC structure
- Model layer: This represents data values associated with the current page.
- The view layer comprises user interface (UI) pages for viewing or changing information.
- Control layer: This layer is responsible for processing user input, determining page navigation and calculating output.
- Business service layers are responsible for data access, business logic, and encapsulation.
ADF Components
Implement the core logic of your Java EE app as one or multiple business services, which allow clients to insert, delete or update business data according to their individual needs while adhering to appropriate business rules.
ADF Business Components is designed to deliver and manage high-performance database-centric applications quickly while adhering to Java EE best practices and design patterns for quick deployment and management of such apps. Oracle ADF contains components designed to facilitate database-centric service development:
Entity object
Entity objects represent table rows and simplify data modification by performing all DML operations directly within them.
Entity objects also allow business rules to be consistently enforced across their lifecycle - linking two objects together through database schema relationships to create layer business domain objects which can then be reused across applications.
View Objects
View objects represent SQL queries and make working with their results simpler. Users can filter, join, sort and aggregate data using SQL to meet any task represented in a user interface.
Connected view objects allow building master-detail hierarchies of any complexity; users also use view objects when editing data via their user interface; once validated, they save changes for storage purposes.
Application Module
A transactional application module allows UI clients to interact with application data. It includes a data model which can be updated, along with procedures and top-level functions (called services methods ) specific to an end user's logical task.
ADF Model Layer
Oracle ADF Model utilizes JSR-227 data controls in its model layer. Data controls abstract implementation technologies used by business services using standard Metadata interfaces, providing details on operations, types and methods involved.
Users can drag-and-drop icons onto pages using JDeveloper to see this information; this also creates bindings between pages and services, while binding information read from an XML document by the ADF Model creates two-way linking mechanisms between the user interface and business services.
Oracle ADF provides ready-to-go implementations of data control for most business service technologies. JDeveloper with Oracle ADF provides an interactive drag-and-drop data binding interface as you create user interfaces with drag-and-drop data binding functionality and support for ADF modules.
ADF Controller
ADF Controller (Advanced Domain Forms Controller Layer) is an improved navigation model and state management for JSF's controller layer that helps manage the page flow of web applications.
JDeveloper lets users build declarative task flows to pass control between various activities such as pages, managed bean methods, case statements or calls into another task flow.
ADF Faces Rich Client
ADF Faces (ADF Faces for short) is an array of JSF standard components equipped with AJAX capabilities built-in.
AJAX utilizes dynamic HTML (DHTML), XML and XMLHttpRequest communication channels; together, these allow requests to the server without needing to re-render an entire page repeatedly. JSF allows server-side control of rich applications using standard internet technologies, thus decreasing JavaScript requirements within AJAX applications.
ADF Faces offers over 100 components, such as tree menus and accordions. Furthermore, ADF Data Visualization Components enable instantaneous views of data through dynamic graphs, gauges and charts with instant Flash/SVG rendering capability and customization, skinning and internationalization support for these components.
- application server
- Application Components
- session beans
- application development process
- application framework
ADF Faces uses JavaScript objects to provide rich functionality through components that display them. ADF Faces' built-in features enable you to develop rich applications without in-depth knowledge of front-end technologies or back-end solutions.
ADF Faces can also be integrated with applications that utilize the Facelets Library, an alternative way to use JSF View Definitions XML technology for view definitions that provides declarative view definitions via declarative XML technology-based view definitions centered around JSF.
Furthermore, Oracle Middleware Web User Interface Developer's Guide for Oracle Application Development Framework includes comprehensive details regarding ADF Faces' architecture and detailed guidance regarding their compatibility.
Create an Application Workspace
Naming and organizing source files for an app are crucial steps towards its creation. At the same time, JDeveloper manages them into projects when using templates to build applications.
Furthermore, it creates and manages any required configuration files according to type.
For instance, a web Application Template (ADF) gives you all the projects necessary to construct a web app using ADF Faces as the view, Pages Flow as its controller, and ADF Components Business Services as its business services.
JDeveloper automatically creates JSF and ADF files when using this template to set up your workspace application.
The Web Application Quick Start Checklist is part of an application overview. This checklist offers basic guidelines for developing web apps.
Links are included to relevant documents and prerequisites while tracking the status of each step. JDeveloper creates two projects using its JScript compiler: Model for business services and ViewController, which contains source files of your ADF Faces View Layer and files related to Controller functionality.
Database Object Modeling
Once your workspace in JDeveloper has been set up, database objects of a schema can be transferred directly into an offline project or database, where they will become offline objects saved as.xml files.
The same editors used for live databases can now also be used within projects to edit/create offline database objects compared to live/offline database versions allowing SQL statements (CREATE/ALTER/REPLACE) statements generated for comparison or comparison against live or offline versions (CREATE, ALTER/REPLACE).
JDeveloper allows you to create either an offline.xml representation of database objects or live modeling them live.
For instance, when you drag tables from connections defined in an application onto diagrams, they allow them to model these database objects online (and therefore create the file) instead. Model database definitions such as foreign keys and tables visually by dragging and dropping keys and columns into place to create, duplicate and move foreign vital relationships.
JDeveloper allows users to work offline by modeling nodes on diagrams in an offline object that will appear in Application Navigator.
JDeveloper automatically updates this database object when editing an active diagram with live schema changes; additionally, these same offline objects may be reused across several diagrams allowing for easier management across projects.
Create Use Cases
It may be beneficial to begin developing an application using use case modeling as a means of communicating user requirements, as shown in figure 1-8 created using JDeveloper UML Modeler and UML Designer's UML Modeler UML diagram viewer - this one shows an end-user viewing their list of orders before drilling down into more details on any given order he wants to view more closely using annotations; you could capture what users will need on screens implemented for that case such as noting each time that any given order listed will have its details selected manually by user when viewing detail screen images on JDeveloper UML Modeler was used.
In this use case model, it noted that each order listed would have its details selected manually by the user selecting which orders listed will have its details selected manually by the user selecting its order details selection option when reviewing them using UML Modeler within JDeveloper for that case study example use case.
Designing Application Control and Navigation With ADF Task Flows
Begin by gathering user requirements before defining which types of pages need to be created to meet them. Next, begin designing the flow of your app.
An ADF task flow can be used in web-based applications as an alternative to standard JSF navigation flows for more straightforward application navigation and transaction management. Task flows provide a modular, transactional approach similar to JSF navigation flows in that most viewable pages remain available through them.
Task flows don't provide instructions for navigation between pages but rather facilitate transitioning activities and may include nonvisual activities that influence an app or page's behavior, like calling managed bean methods, evaluating expressions or initiating another task flow - making business logic independent from how a page looks and allowing reuse.
- application architecture
- archive file
- deployment descriptors
- database connections
ADF Controller offers an approach for declaratively specifying navigation using flow control rules, with information regarding these and other flow details saved into configuration files for later reference.
Task flows go beyond pages: they can coordinate fragments of pages composed of JSF or JSP files that display content on other JSF pages.
Bound task flows allow you to combine all these fragments onto one new page with their associated task flows, thus creating one entity that has the power to execute independently, evaluate expressions and display content without altering its parent page's content in any way.
When creating new users for registration applications must first determine what kind of user should be created - all logic for doing this lies within the user-registration-task-flow task flow, which becomes part of registerUser page using regions from user-registration-task-flow used as regions within registerUser page as it serves a region and task flow containing regions with all this logic being handled within user registration-task-flow task flow which then forms part of registerUser page itself containing regions containing logic used throughout its contents containing page itself containing its regions!
For example, user registration is performed before creating them (all logic involved here being handled within user registration-task-flow task-flow).
All logic involved here would reside somewhere within the registerUser page to which its registerUser. Its registration-task-flow task-flow region is used within registerUser. Regions can also facilitate reuse. You can create a Task Flow region and identify what information pieces it requires as parameters/return values; drag this onto any page within an application to reuse this piece based on the value returned, possibly with different views displaying depending on that value returned from tasks completed within it.
Identification of Shared Resources
Some aspects of your application require repetition: for instance, address creation may appear whenever users register and create orders; or during the development phase, specific components should be deployed throughout your software solution.
Declaratively creating ADF libraries gives you the power to produce artifacts that can be packaged and utilized throughout an application. For instance, when building addresses, you could create an address process flow which can then be packaged up as a resource library and shared among developers who will add the task flow as part of their catalog of resources and add it to any page they need for reuse if required.
When designing an application, always remember all reusable tasks when planning.
- deployment descriptor file
- Fusion Web Applications
- application deployment descriptor
- programming model
- Oracle Enterprise
- application module instances
- Applications window
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Create A Layer Of Business Domain Objects For Tables
Once you understand the data you will present and manipulate in your application (for additional details, please visit "Designing Databases' ' within "Designing and Developing Applications" of JDeveloper Online Help), entity objects should be created to represent tables.
Entity objects allow more straightforward data modification for multiple pages with consistent validation/access rules across each. JDeveloper automatically configures projects while working to include Oracle ADF architecture that your app might require at runtime.
Your first task in creating entity objects from database tables should be creating entity objects with relationships to those tables reflected by associations between entity objects.
Alternatively, create these first and then build database tables based on them. After creating objects, they can be enhanced with custom behavior by clicking here for further instructions.
Developing the Business Services
After creating the layer of reusable business objects, an application module may be implemented. An application module includes data models and service methods that user interface users can utilize.
View object components you have developed can help create the data model for an application module, with queries built directly into each view object used to join, aggregate, filter and sort data to meet user interface task demands. View objects also help reference entity objects by reusing business domain layers when users wish to update data; view objects can even be reused across application modules!
View objects can be configured with display properties to ensure consistent data display across pages. Metadata makes setting display properties simple - once configured, you change as necessary instead of simultaneously making modifications across all of them! You can manage queries by specifying information specific to that particular page.
Ultimately, this ensures all display functions remain in their proper places.
Testing and Debugging Business Services with the Business Component Browser
The Business Component Browser makes it possible to check business services while developing your application iteratively.
Use it to quickly test queries, logic and validation without creating interfaces - saving both time and energy when diagnosing issues! For more on testing and developing application modules Implementing User Interfaces with JSF
- client tier
- task flow activities
- programming model
- Server Applications
JDeveloper comes equipped with predefined layouts using these components that you can easily incorporate into your page layout using ADF Faces components, providing an effortless means of choosing how you wish to arrange pages - whether three or four columns.
Furthermore, themes may also be applied as necessary, and additional information on these can be found in Oracle Middleware Web User Interface Developer's Guide for Oracle Application Development Framework section "Using Quick Layouts".
Oracle ADF allows developers also to create customized templates for pages. Developers can utilize templates to determine how pages will be laid out (using either Quick Layout Templates or manually), add content that should appear across pages, and insert placeholder attributes based on changes made to any template used for pages that use that template.
When changing, any one of them will reflect these updates.
StoreFrontModule templates are most frequently employed for pages. These designs include sections dedicated to branding and navigation and content divided into three panes with footers - which the template designer may change at any point while creating their template.
Error Handling and Validation
You can use the Overview Editors for Entity and View objects to add validation declaratively and customize what message will be shown when validation fails, scripted expressions if needed as supplementations of declarative validations - please see more details regarding creating validations at the service level here.
ADF Faces provides built-in capabilities for validating input components. You can set one or more validators on any component by either setting an attribute as required, using prebuilt ADF validators, or creating custom validators to suit your specific needs - for more details, please see Chapter 12, "Validating Input and Converting Inputs'' of Oracle Middleware Web User Interface Developer's Guide for Oracle Application Development Framework.
Add Security
Oracle ADF features the Java Authentication Authorization Service-based security implementation called JAAS through the Java Community Process.
JAAS serves to authenticate and enforce authorization within applications; Oracle's implementation uses permission-based security where permissions are defined for application roles related to users within your application - more details on secure apps here.
Debugging and Testing the Web Client Application
Testing an Oracle ADF Web app follows similar testing procedures as any Java enterprise application development; most errors stem from simple issues related to declarative data that an application specifies or the EL statements which refer to Oracle ADF binding containers; often, the issues can be easily remedied through examination of these declarative files or expressions.
JDeveloper provides the ADF Logger to capture runtime messages sent by ADF Model Layer API and quickly identify errors by searching this log file for errors.
In addition, there's also the Declarative Debugger, which lets you set breakpoints; when one has been reached, the application execution will stop, and you can explore and compare how Oracle ADF Binding Container works against expectations data.
Read more: The Role of Web App Development in Business Planning
Refactoring Application Artifacts
JDeveloper makes it simple and fast to move or rename components of your application, such as view objects. JDeveloper then propagates any necessary changes directly to the metadata XML file for you.
Integrating Web Applications
Oracle SOA Suite's service-oriented architecture (SOA) principles enable you to easily incorporate any web app into existing apps or build brand new ones, using declarative tools provided with Oracle SOA Suite that allow integration across services, events and business rules.
Your application modules can be made public as services and used as part of business processes by creating events to initiate them.
Working Productively in Teams
Most applications are developed collaboratively using team processes "Developing with Oracle ADF." However, developers often create components of applications simultaneously.
For an efficient development process, team members should divide work according to standards while being able to access files through source control systems and manage them effectively.
Before commencing any large-scale application development project, an in-depth design phase should take place to identify and assess potential use cases and task flows and plan screen layouts and designs.
Below is a list of tasks for an application once its initial design has been finalized:
Infrastructure
DBAs utilize Ant scripts or other script files to develop and deploy applications. In contrast, SQL scripts create the database schema that their applications need.
Entity Objects
A team of developers works on developing entity objects in an expansive development environment. Entity objects are integral to your application's functionality, so completion should come quickly during development.
Oracle ADF Libraries provide an effective means to share finished entity objects among different teams and for them to add them to the Resource Palette catalog. However, you don't have to do this when developing apps; many applications may feature entity objects (and view objects) created by one individual or team.
View Objects
Once the entity objects have been constructed as part of an enterprise project or library, view objects can be utilized to display data within a UI interface, provide service data objects for other applications or even serve as service objects.
Each developer was responsible for building view objects when creating an Order Demo page; due to this tight integration between Order Demo pages and view objects.
Your investigation may reveal multiple view objects with similar functionality, making combining these view objects possible by altering one object to meet each page or service's demands more effectively.
Once view objects are created, data controls and custom methods can be added to an application module by creating view objects iteratively and checking for redundant code before adding.
User Interface (UI) Creation
Either the team that developed the view object, as stated previously, can build its corresponding UI; alternatively, you could employ a separate team.
You could also implement a "UI first strategy," where designers create pages even before data controls have been added - Oracle ADF provides placeholder controls so that this process may start earlier on in development cycles.
Standards
Standardization is vital when working in multiple teams on app development. Prior to development, implement a set of standardized practices so all components operate effectively together.
Standardizing is especially necessary in areas like these when you collaborate as part of a group:
Code layout style
Using a specific code style is essential so that multiple people can efficiently work on the code. JDeveloper lets you customize the behavior of its built-in editor.
Many settings influence how the user interacts (such as the display settings) with the code editors, while others impact how code is formatted. You can choose a style of code that will determine things such as the position of the opening brackets or the size of the indents.
It is possible to import existing styles or create new ones and export them so that the whole team can use them. See "Setting preferences for the source editor" under the "JDeveloper basics" section of the JDeveloper Online Help.
Conventions For Naming Packages
When creating packages, names must reflect what types of objects will reside inside each and how many exist. All managed beans within StoreFront Module reside within its package view.
Managed; for all util packages (one Oracle ADF and JSF), any beans with helper methods accessible by beans from different packages (i.e. ADF/JSF); finally, the standard package holds all property files.
Pages
As previously discussed, templates can help developers working on user experience create uniform pages with consistent appearance and feel across pages that use it.
Furthermore, any time changes are made to this template; it will show up immediately on any pages using it.
Not only should you use templates, but you should also create a standard for naming pages. For instance, your name should reflect where the page sits within your application.
Achieve this through creating subdirectories that add another level of organization.
Connection names. Unlike JDeveloper objects and Oracle ADF objects that can only be created once for each project and have the same name regardless of who uses or sees them, database connection names may be created by different team members even though all details remain the same.
Any discrepancies could create conflicts. Everyone in your group should agree upon one case-sensitive connection name that should be utilized across your team members.
How to Use a Source Control System
Working together as part of a team requires using a source-control system; Oracle JDeveloper integrated support for CVS, Subversion and other source-control systems like Trac.
You may even create extensions for another source control system within JDeveloper itself! For information on using these systems in JDeveloper, please see "Using Versioning '', located under "Designing and Developing Applications' ', of its Online Help documentation.
Learning Oracle ADF
Oracle offers several resources that will assist in learning more about their ADF solution and incorporating it into an application:
JDeveloper Cue Cards
Offer step-by-step guidance for Oracle ADF application development. Featuring examples and sample schema, as well as your data, these cue cards provide step-by-step instruction that makes application development straightforward.
Incorporating code samples and topics providing more background knowledge - Oracle ADF Cue Cards provide a quick and effective way to gain knowledge in basic ADF concepts and tackle simple tasks efficiently and swiftly.
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Conclusion
Oracle Application Development Framework offers an efficient and robust method for building web-based apps using Oracle technologies.
ADF offers a complete toolset, including visual components and data binding abilities, that streamlines development processes while increasing productivity by creating feature-rich applications more quickly and cost-effectively than with alternative approaches such as the CSS framework.
Oracle technologies integrate seamlessly to provide connectivity, scalability and compatibility while the learning curve and licensing fees should all be carefully considered; ADF remains a top pick to build enterprise web apps using these cutting-edge solutions! Conclusion: ADF uses these Oracle technologies by making development of fast, robust web applications using Oracle technologies, making ADF an excellent option when used by enterprises using these Oracle technologies in designing enterprise web app development processes.
