Web project - folder structure

Web Deployment Descriptor

web.xml file

JavaSource (or src/java)

Contains the project's Java source code for classes, beans, and servlets. When these resources are added to a Web project, they are automatically compiled and the generated files are added to the WEB-INF/classes directory. The contents of the source directory are not packaged in WAR files unless an option is specified when a WAR file is created.

imported_classes folder

This folder may be created during a WAR import, and contains class files that do not have accompanying source. The imported_classes folder is a Java classes folder; Java classes folders can also be created using the Web project Java Build Path properties page.

WebContent (or web) folder

The mandatory location of all Web resources, including HTML, JSP, graphic files, and so on. If the files are not placed in this directory (or in a subdirectory structure under this directory), the files will not be available when the application is executed on a server. The Web content folder represents the contents of the WAR file that will be deployed to the server. Any files not under the Web content folder are considered development-time resources (for example, .java files, .sql files, and .mif files), and are not deployed when the project is unit tested or published.

META-INF

This directory contains the MANIFEST.MF file, which is used to map class paths for dependent JAR files that exist in other projects in the same Enterprise Application project. An entry in this file will update the run-time project class path and Java build settings to include the referenced JAR files.

theme

The suggested directory for cascading style sheets (css) and other style-related objects.

WEB-INF

Based on the Sun Microsystems Java Servlet 2.3 Specification, this directory contains the supporting Web resources for a Web application, including the web.xml file and the classes and lib directories.

/classes

This directory is for servlets, utility classes, and the Java compiler output directory. The classes in this directory are used by the application class loader to load the classes. Folders in this directory will map package and class names, as in: /WEB-INF/classes/com/mycorp/servlets/MyServlet.class.This is generated while a build happens. Do not place any .class files directly into this directory. The .class files are placed in this directory automatically when the Java compiler compiles Java source files that are in the Java Resources directory. Any files placed directly in this directory will be deleted by the Java compiler when it runs.

/lib

The supporting JAR files that your Web application references. Any classes in .jar files placed in this directory will be available for your Web application. In short, jar's file would be in classpath.

Libraries

The supporting JAR files that your Web application references. This folder mirrors the content of the lib folder. In addition, Web Library Projects, which are "virtual" JAR files that do not physically reside in the Web project, but are associated with Java projects elsewhere in your workspace, are included in this folder. They are packaged with your project when you export the application's WAR file.

 A library entry on the Java build path will remain there unless the actual JAR file is deleted from the WEB-INF/lib folder. If you remove a library path entry but not the JAR file, the library entry will be re-added to the path automatically.

[Ultimate Reference: http://java.sun.com/blueprints/code/projectconventions.html ]

How to Call PL/SQL from ADF?

You can use the following code to call a pl/sql block from the ADF bc Application module.


public void executePlsqlProcedure(){

CallableStatement updateStmt = null;
try {
// Put your PL/SQL block in a String variable.
String Stmt = "begin delete test_table where header_id = :1; "+
" :2 = xxx_pkg.yyy_function(); end;";
OADBTransaction txn = getDBTransaction();

// Pass the PL/SQL block to the callable Statement
updateStmt = txn.createCallableStatement(Stmt, 1);


// Set all the bind variables before calling the execute command
updateStmt.setInt(1, headerIdToDelete);

// And register the output parameter types
updateStmt.registerOutParameter(2, Types.DOUBLE);
updateStmt.executeUpdate();

// After execute you can get the value of pl/sql block output
Number amount = new Number(updateStmt.getDouble(2));
updateStmt.close();

// Commit the transaction in the database
txn.commit();


} catch(SQLException sqle) {
updateStmt.close();
}

}



And you can call the above Application Modules method from managed bean using following code.

FacesContext facesContext = FacesContext.getCurrentInstance();
ExpressionFactory exp = facesContext.getApplication().getExpressionFactory();
DCBindingContainer bindingContainer = (DCBindingContainer)exp.createValueExpression(facesContext.getELContext(),"#{bindings}",DCBindingContainer.class).getValue(facesContext.getELContext()); 
DCIteratorBinding itr = bindingContainer.findIteratorBinding("Dept1Iterator"); 
DemoAppAMImpl svc = (DemoAppAMImpl)itr.getDataControl().getApplicationModule();


Or you can call this method by exposing into client interface.

System.out.println

This is the most commonly asked question in web applications development in jdeveloper including OA Framework, ADF, ejb, web services etc.


Can I leave System.out.println or System.err.println in the production code?

System.out.println comes handy when debugging the application because you can see the messages pretty much easily in the jdeveloper console. And it takes relatively less time than the debugging option in Jdeveloper. So even experienced developers use it for debugging. You may think, "Anyway this doesnot any affect in the production system". But actually System.out.println statements will have serious performance issue in the production system if you fail to remove them in the final code.

The reason is that the application server will have only one output stream and one error stream in the JVM. Hence multiple threads calling the System.out.println() have to be synchronized.

Considering the production system with thousands of users, back end programs, webservices, scheduled process running parralley in the machine. Calling system.out.println() will potentially block the performance of whole system.

Also the application server doesn't redirect the std out to a file, and is lost.



Hence always remove the System.out.println() /System.err.println() from the production code.

Managed Bean

Managed beans are Java classes that you register with the. The managed beans are initialized when they are referenced in the application for the first time. It helps to handle UI events or write data manipulation code. TIP: Use managed beans to store only logic that is related to the UI rendering.

Managed beans can be registered in three files

1. adfc-config.xml
2. Task flow definition file
3. faces-config.xml

adfc-config.xml

Managed bean declared in this file can be of any scope.

Task Flow definition file

Managed bean scope can any scope. However, managed beans of request, pageFlow, or with scope set to none accessed within the task flow definition, must be defined within the task flow definition file. Managed bean definitions within task flow definition files will only be visible to activities executing within the same task flow.

faces-config.xml

Allows any managed bean scope other than pageFlow scope.

The order of searching a managed bean in the application is faces-config.xml, adfc-config.xml and Task flow definition file (if exists). Hence managed bean defined in the faces-config.xml takes the precedence.

As a general rule in fusion web applications, a bean that may be used in more than one page or task flow is defined in the adfc-config.xml and a bean that is used within the task flow is defined in the task flow definition XML file.

Add a managed bean

To add a managed bean

1. Click the adbc-config.xml file or task flow definition file.
2. Go to Property editor -> Managed bean tab
3. Choose the +(Add) Icon.

Difference between Managed Bean and Backing Bean

Backing bean and Managed bean are not different they are the same. Managed bean is about how the bean is created and initialized. Backing bean is about the role a particular managed bean plays.

In other way, Managed bean is a Java Bean registered in the adfc-config.xml file. These beans have properties that are bound to the values of UIComponents.

Backing bean is a special type of managed-bean consisting of properties that are UIComponents. Instead of the bean properties being bound to the UIComponent values, they are instead bound to the UIComponents themselves.

Bounded and Unbounded Task Flows

Unbounded
A specialized form of task flow that has a single entry point and zero or more exit points. It is configured in adfc-config.xml file.

• It cannot declaratively specify parameters.
• It contains default activity
• It cannot be called by another task flow.

Unbounded task flow can be used when

• You want to take advantage of ADF controller features not offered by bounded task flows
• You don’t need ADF controller features that are offered when using a bounded task flow.
• The task flow will not be called by another task flow.
• The application has multiple points of entry.

Bounded
A set of activities, control flow rules and managed beans that interact to allow a user to complete a task. It is used to encapsulate a reusable portion of an application.

• A bounded task flow can be called another bounded task flow or unbounded task flow.
• The bounded task flow always specifies a default activity
• Managed bean specified in pageFlow scope is visible only within the task flow, and isolated from rest of application.

Because of the resuability features, bounded task is mostly used in all applications.


Features of Bounded Task Flow

1. Well-defined boundary An ADF bounded task flow consists of its own set of private control flow rules, activities and managed beans. Input and Ouput parameters are available to bounded task flow just like a function call. Data controls can be shared between task flows.
2. Single point of entry An ADF bounded task flow has a default activity that executes before all other activities in the task flow.
3. PageFlow memory scope Its a new scope introduced in ADF. And its lifespan is ADF bounded task flow.
4. Reuse You can identify an entire group of activities as a single entity and reuse it in another application.
5. Parameters and return values You can pass the parameters and get the output just like a function call.
6. Transaction ManagementIt represents a transactional unit of work. While entering a bounded task flow you can create new transaction or join the existing one.
7. Reentry You can choose to reenter the bounded task flow.
8. Security Secure a bounded task flow using fusion security.

OAF vs ADF 10g

OAF vs ADF 10g

Hi all,

With the emergence of next generation Fusion technology middleware stack there is confusion between the technologies OA framework and ADF among Oracle developers especially for the people who are developing extensions for Oracle Applications 11i/R12. Both are Oracle technologies for developing web based User Interface with Jdeveloper. Hence I decided to bring out the detailed overview of OA framework and ADF, and identify the rite technology for your web development projects.

OA Framwork

OAF (Oracle Applications Framework) is used to create the web based Oracle Application extensions and it is the default web technology for 11i and R12 development. It is closely integrated with Oracle Apps hence it is meaningless outside apps context. OAF is a model-view-controller technology stack which comprised of OA framework View (regions and pages) and BC4j respectively as view and model layers.

OAF and Oracle Applications 11i/R12

• OAF includes AOL which provides e-business functionality like functions, menus, responsibility, functional security, data security, messages, profiles, flexfields, and concurrent programs.
• List of Values – validation, auto complete, auto clear is available in OAF.
• Transactional Search – Query Bean is available in OAF.
• Data export, Configurable pages and Rich text editor is available in OAF.
• OAF supports translatable table (TL tables).
• Who columns like created by, modified by, creation date, modified date are supported in OAF.
• Since OAF is tightly integrated with E-Business session management is done automatically.
• Menu that appears at the top of the page is integrated with AOL menus. Hence the menus can be configured dynamically by manipulating AOL menus and no coding is required.
• Functional security is available in OAF which allows you to configure the responsibility dynamically for the user.
• User authentication is done from SSO. So no need to configure or write any code.
• Data security is available.
• Secured against cross site scripting attack.
• OAF page access can be tracked.
• Standards and guidelines are available for developing extensions in OAF which is the most important thing.
• Reusable regions are available in OAF.
• UI cannot be migrated to ADF 11g (may be in the future Oracle will come up with migration utility for UI but even then only declarative pages would be migrated and the UI pages should have followed the coding standards strictly).
• BC4J can be migrated with minimal code change.
• Controller cannot be migrated hence you have to rewrite all the logics in the controller if you want to migrate it to ADF 11g.

ADF 10g

ADF 10g (Application Development Framework) is the core technology for Fusion Applications and uses lot of open standards and technologies. ADF can also be used for common J2EE applications because ADF technology stack allows you choose between various options. ADF is primarily comprised of ADF Faces, ADF model and ADFbc (which is previously known as bc4j in OAF)

ADF 10g and Oracle Applications 11i/R12

• ADF 10g does not include any support for AOL
• List of Values and its associated features like validation, auto complete and clear does not exists in ADF.
• No Transactional search, Data Export, Configurable pages or Rich text editor.
• No support of Translatable Table and who columns.
• No support for E-business suite session management.
• No support for integration with Oracle Workflow.
• E-business security features are totally unavailable in ADF 10g. (security features include Data security, functionally security, SSO etc)
• Page access cannot be tracked in ADF 10g.
• No support of for menus in ADF.
• Reusable regions cannot be created in ADF 10g.
• ADF 10g can be easily migrated to ADF 11g.
• And most of all you cannot extend or personalize the existing page with the help of ADF.

And the advantage of ADF 10g over OA framework is that your investments would be protected when you want to migrate to ADF 11g.

(ADF has many advantages starting from the underlying architecture, the level of support for Web Services and SOA development and going all the way to the actual development experience of UIs using visual editor and drag and drop binding. -- Shay)

Conclusion

Consider following points when choosing technology.

• If you want to build few pages with close integration of e-business suite then opt for OA framework. Remember if you want to migrate your code to ADF 11g in the future, you have to follow the coding standards strictly and code all the business logic in bc4j rather than handling the logic in controller.
• If you don’t want a close integration e-business suite or your building entirely new application then go for ADF 10g.

What is Oracle ADF?

It is a new framework developed by Oracle to solve the complexity of the J2EE platform, and which is based on the MVC model, such as: 
- Allows to concentrate on the business logic 
- Based on the standards of the development industry 
- standard Expression Language (EL) for web clients 
- standard Components for Java Swing GUI client 
- Supports various server-side technologies: Oracle ADF Business Components, Oracle Application Server TopLink, EJB, web Services, Java Objects ... 



Architecture Framework

Configuring logging for ADF application

In this post i will show you how to configure ADF logger that logs your messages/errors to a specific log file.  Here are the steps needed to do the configuration.

1. In JDeveloper right click IntegratedWeblogicServer instance, and choose Configure Oracle Diagnostic logging for "IntegratedWeblogicServer".

2. Choose the root logger, and in structure window expand log_handlers, copy log_handler named "old-handler".

3. Paste the copied log_handler and name it XX-custom-handler, from property window change .

4. Choose the path property and change its default value.

5. In the overview tab of logging.xml file, click the add symbol to add a persistent logger. In the logger name select the class file or package for which you want to use this logger. example : xx.oracle.app select a level based on the severity you need.

 

6. Expand the Root logger and choose the newly created logger, and in the handler declarations window press the add icon, and choose the custom handler.

7. Now select your project in the application window, and double click it to change the run configuration java options -> Choose the default run configuration -> Edit -> Java options and add the following option "-Djbo.debugoutput=adflogger".

8. Now you can use the ADFLogger util to create a logger instance that logs to you log file.

Done.

Sample ADF CRUD web application

In this post i will show you how to use ADF to create a simple CRUD application in just few minutes.

To know more about ADF "Application development framework" please go to this link.

1. Create an ADF web application.

2. Set application name "Sample Crud" and click finish.

3. Choose "Connect to a Database" and press "Create a Database Connection".

4. Put connection details, and connect to the Oracle Sample HR database, and make sure to test the connection.

Note: Make sure that the hr user is not locked, and if its locked you may need to unlock it.

5. Mark the "Connect to a database" step as Done.

6. Expand the "Build Business Services" step and click "Go to Substeps".

7. Expand "Create Entity Objects and Associations", Press "Create Entity Objects and Associations".

8. Choose the model project.

9. Choose the database connection created in step 3.

10. Press the Query button, and move the Jobs table to the right column.

11. For the updatable views, chose JobsView and move it to the right column, then press finish.

12. Mark the "Build Business Services" step as Done.

13. Open the "adf-config" unbounded task flow.

14. From the "Component Palette" panel drag the view icon to the task flow.

15. Rename it to "jobsView" and double click on it, and then click Ok.

16. Drag a button from "Component Palette" panel into the page, and rename it from the property panel.

17. Do the same for the Edit, Delete, View buttons.

18. From the "Data Control" panel, drag the JobsView1 into the page, and insert it as a read only table.

19. Choose "Single Row" for selection, and click Ok.

20. Back to the "adf-config" unbounded task flow, and drag a new view for the job form.

21. Double click the new page, and drag the JobsView1 into it from the "Data Control" panel as a form.

22. Check the "Include submit button" checkbox, and click Ok.

23. Back to the "adf-config" unbounded task flow, and drag a new view for the job details.

24. Double click the new view, and add the JobsView1 into it as a read only form, and click Ok.

25. Back to the "adf-config" unbounded task flow, In the "Data Control" panel, expand the JobsView1 -> Operations and drag the "CreateInsert" operation into the task flow.

26. Do the same for "Delete" operation.

27. From "Data Control" -> Operations, drag "Commit" and "Rollback" operations into the task flow page.

28. From the "Component Palette" panel click the "Control Flow Case" icon and drag from "jobsView" page to the "viewJobDetails" page, and name it "view".

29. Do the following to complete navigation flow for our business case:

A. "create" flow from "jobsView" to "createInsert" operation.

B. "edit" flow from "jobsView" to "jobForm" page.

C. "delete" flow from "jobsView" to "delete" operation.

D. "CreateInsert" flow from "CreateInsert" operation to "jobForm" page.

E. "Delete" flow from "Delete" operation to "Commit" operation.

F. "save" flow from "jobForm" page to "Commit" operation.

G. "cancel" flow from "jobForm" page to "Rollback" operation.

H. "Commit" flow from "Commit" operation to "jobsView" page.

I. "Rollback" flow from "Rollback" operation to "jobsView" page.

J. "back" flow from "viewJobDetails" page to "jobsView" page.

30. Go to the "jobsView" page, and double click it, and from the property panel, change the action for each button to be as follow:

A. "View" button action = "view"

B. "Create" button action = "create"

C. "Delete" button action = "delete"

D. "Edit" button action = "edit"

31. In the "jobForm" page, add a new button and name it cancel, and the action = cancel, imediate=true.

32. In the "viewJobDetails" page add a new button and name it back, and the action = back.

33. Right click the adf-config unbounded task flow and click run, if prompted to choose the run configuration choose "jobsView" page to be the start page.

34. Screen shots for the application:

Done.