Oracle Magazine - May/June 2011

ORACLE ADF
Contextual Events is an Oracle ADF feature
that enables developers to implement
view-to-region, region-to-view, and region-
to-region communication.

Right-click EventHandler.java in the Application Navigator and choose Create Data Control. This step exposes the event handler methods in a JavaBean data control. Next select the DataChangeDisplayPageDef.xml file entry in the adf.sample.oramag pageDefs package and select View -> Structure from the main menu. In the Structure window, right-click the bindings node and choose Insert Inside Bindings -> Generic Bindings -> methodAction. In the Create Action Binding dialog box, select the EventHandler data collection and choose one of the two event handler methods in the Operation list. Click OK, and repeat the same steps for the other method. In the Structure window, expand the two method bindings you’ve just inserted and note that each has a customPayLoad argument, as shown in Figure 1.

Next you’ll deploy the contextual event consumer in an Oracle ADF library. In the Application Navigator, right-click the Mirror TaskFlow project and choose Deploy -> OraMagMirror TaskFlow. Then click Finish in the Deployment Action dialog box. The Oracle ADF library JAR file is created in the project’s Deploy folder.

use this name later to identify the producer event when mapping it to the event handler. The Raise Condition tab enables you to enter an expression language (EL) expression defining a condition under which an event is propagated. On the Documentation tab, you can enter a text description of the event producer; the description is visible when you map the producer to event handlers. Leave the Raise Condition and Documentation tabs unchanged, and click OK.

DCBindingContainerValueChangeEvent is the event object class that is passed for Oracle ADF–bound value changes. (If an input field is not Oracle ADF bound, the payload object will be javax.faces.event .ValueChangeEvent.)

In the Application Navigator, select the DepartmentsViewPageDef.xml file in the adf.sample.oramag.vi ew.pageDefs package and open the Structure window. Expand the bindings -> DepartmentName node to see the event definition you created for this attribute.

Now you’ll create a second producer event—one with a custom payload. In the visual editor for the DepartmentsView.jspx file, click the Submit Custom Payload button and create a new contextual event from the Contextual Events category in the Property Inspector’s Behavior section. Enter commandActionCustPayLoad for Name. Check the Pass Custom Value from box. Choose the Page Data option, and select the ManagerId entry, as shown in Figure 2. By doing so, you’re overriding the default payload object (javax.faces . event.ActionEvent) and replacing it with the ManagerId value. Click OK to create a new eventBinding definition of type javax.faces.event.ActionListener in the DepartmentsViewPageDef.xml file. This contextual event will fire when a user clicks the application’s Submit Custom Payload button.

The eventBinding is referenced from the button’s ActionListener property with expression language: #{bindings.eventBinding

Figure 2: Creating a contextual event producer with a custom payload

. listener.processAction}. Developers can also invoke contextual events from Java code in a managed bean by casting the eventBinding reference to JUEventBinding and calling the getListener method.

CREATING PRODUCER EVENTS

Now you’ll switch to a different project and create two contextual event producers. Open the OraMagMirror TaskFlowConsumerApp.jws workspace, located in the starter-app folder.

First you’ll create a producer event without a custom payload, so that the event object will become the payload by default. In the Application Navigator, double-click the DepartmentsView.jspx file in the View Controller project. In the visual editor, select the DepartmentName field and open the Property Inspector. In the Property Inspector, open the Behavior node, scroll to Contextual Events, and click the green plus (+) icon under the Published Events header.

Select Create New Event, and enter
departmentNameChange for Name. You’ll

ADDING REGIONS FROM THE ORACLE ADF
LIBRARY TO THE APPLICATION

Now you’ll add the event handler regions to the sample application. The first step is to create a Resource Catalog file connection to the Deploy folder holding the Oracle ADF library JAR file you created earlier. Choose View -> Resource Palette from the main menu, and click the folder icon at the top. Choose New Connection -> File System, create a connection with the name Oramag TaskFlow, and then browse to the starterapp/mirrortaskflow/deploy folder to fill in the directory path. In the Application Navigator, select the ViewController project. Then, in the Resource Palette, expand the file connection and select the OraMagMirror TaskFlow.jar library, making sure the ViewController project is still selected in the Application Navigator. Right-click the library and choose Add to Project. In the Confirm Add ADF Library dialog box, click Add Library.