tell me more icon Bounded Task Flow

An ADF task flow is a reusable unit for defining control flow between activities in an application. Each task flow in the application contains a portion of the application's navigational graph, enabling users to complete a task. For example the following illustration shows a simple task flow with two activities, Create and Confirm. The arrows between the activities are known as control flow cases. Activities could be view pages, method calls, or operations calling other task flows.

Simple task flow

An ADF bounded task flow is a specialized form of reusable task flow that always specifies a default activity, which is the single point of entry that must execute immediately upon entry of the bounded task flow. A bounded task flow allows input parameters, return values, and reentry.

The Create Task Flow dialog lets you create bounded task flows or unbounded task flows. An unbounded task flow consists of all activities and control flows in an application that are not included within any bounded task flow. In the example, you select Create as Bounded Task Flow to define a bounded task flow, and you deselect Create with Pa ge Fragments so you do not associate view activities with page fragments.

Create Task Flow dialog, bounded task flow

When you click OK in the Create Task Flow dialog, JDeveloper does the following for you:

  • Creates the XML source file for the bounded task flow, orders-task-flow-definition.xml.
  • Opens the bounded task flow in the task flow diagrammer (default). Initially, the diagram is a blank canvas. If the diagrammer is not the current editor, click the Diagram tab at the bottom of the editor window.

Blank canvas, task flow diagrammer

In the example, you will create activities and control flow cases on the task flow diagram for navigating between a Browse page and a More page.

Task Flow Diagrammer

The default activity will be Browse, which is indicated by a green background on the Browse page icon. The Browse activity will display an abbreviated Orders form with navigation buttons for browsing all order records. The More activity will display the full Orders form for the current order shown on the abbreviated Orders form. Initially both page icons on the task flow diagram have yellow warning symbols, which indicate that the physical page files (for example, Browse.jspx) have not yet been created. To create the actual page file, you will double-click a page icon to open the Create JSF Page dialog. Once the page is created, the yellow warning symbol on the page icon will be removed.

To see the metadata JDeveloper adds for you when you create the task flow diagram using the diagrammer, click Source in the editor window to switch to the XML editor.

In a task flow definition, the top-level element is <adfc-config>, which is the element that appears first in all ADF Controller XML source files. Activities and control flows in a bounded task flow are defined inside <adfc-config>, within the <task-flow-definition> metadata element.

The bounded task flow is identified by the id attribute of <task-flow-definition>. The <control-flow-rule> and <control-flow-case> elements specify the control flow rules for each view activity. The <view> elements correspond to the view activities in the task flow.

After you create the physical .jspx page files, JDeveloper will add further metadata that identify the physical JSF page file name. For example:

                               
<adfc-config xmlns="http://xmlns.oracle.com/adf/controller"...>
  <task-flow-definition id="orders-task-flow-definition">
  ...
    <view id="Browse">
      <page>/Browse.jspx</page>
    </view> 
  ...
  </task-flow-definition>
</adfc-config>
                            

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