About the Oracle ADF Bindings

Oracle Application Development Framework (Oracle ADF) provides several types of binding objects to support the attributes and operations exposed by the Oracle ADF data controls for a particular business object:

Iterator binding, one per accessor attribute that your page or panel displays. Iterates over the business objects of the data collection and maintains the row currency and state.
Value bindings, one for each databound UI component. Provides access to data.
Action binding, specifically defined for a button component. Provides access to operations defined by the business object.

You create these bindings in JDeveloper through your interaction with the Data Control Palette, a visual editor, the Structure window, and the Property Inspectory. You can view the binding in your application in any one of several ways:

In the source code view of a web page, where binding references appear in expressions that get evaluated at runtime using the expression language (EL) features. In the code view, the expression looks like this:

<c:forEach var="rv" items="${bindings.DataBindingObject.theCollectionProperty}"

The data binding object accesses the Oracle ADF binding container through the bindings variable, which is a variable that specifies the namespace for the binding containers in the ADF binding context. The binding container is initialized for Model 2&ndashstyle web applications in the Oracle ADF class oracle.adf.controller.struts.actions.DataAction.

Note: Although the data action class does not appear in your project, you can see that the action mapping for the data action appears in the struts-config.xml file, which defines the modelReference property to initialize the binding container from the pageNameUIModel.xml file.
In the code view of a JClient panel or form, where the setModel() method call on the UI component initializes the data binding object and accesses the binding container through the ADF binding context (specified by the setBindingContext() method call on the data panel).

The binding container is initialized from the PanelName UIModel.xml file in the JClient project when the panel binding is created (by the JUPanelBinding panelBinding constructor).
In the Structure window for either client type (web page or JClient panel), where the data binding objects defined for each UI component in your view document appear in the (UI Model) tab. To edit the declarative properties of the binding definitions, right-click and choose Edit. To understand what values you can set for runtime-only properties, select the binding node and press F1.

The following sections describe the various bindings.

About the Iterator Binding

The oracle.jbo.uicli.binding.JUIteratorBinding class implements the iterator binding.

The iterator binding is a runtime object that your application creates to access the Oracle ADF binding context. The iterator binding holds references to the bound data collection, accesses it, and iterates over its data objects. The iterator binding notifies value bindings of row currency and row state. Then, value bindings that you define allow UI components to display or update the current data object of the collection being iterated over. In this way, the iterator binding provides uniform access to various collection types from different business services.

In the case of an ADF Business Components view object, the ADF bindings for the UI components may be able to display a row currency indicator. In a table, for example, the current row is identified at runtime by an asterisk (*) symbol displayed in the first column of that row. The currency indicator is available only through the iterator binding when the bound view object has a key attribute defined. When no key attribute is defined for the bound view object, each row of the table will display the asterisk. In this case, you can edit the UI component in the visual editor to prevent the asterisks from displaying at runtime.

The iterator binding defines its own set of runtime properties.

About the Value Bindings

Attribute Value Binding

The oracle.jbo.uicli.binding.JUCtrlValueBinding class implements the attribute value binding.

The attribute value binding permits the databound UI component to obtain the attribute value of the specified collection's data object. Depending on the type of UI component, users may view and, in some cases, edit the value of the attribute.

The attribute value binding defines its own set of runtime properties.

Boolean Value Binding

The oracle.jbo.uicli.binding.JUCtrlBoolBinding class implements the boolean binding.

The boolean binding obtains the attribute value of the specified collection's data object based on the control's selection state.

The boolean value binding defines its own set of runtime properties.

List Value Binding

The oracle.jbo.uicli.binding.JUCtrlListBinding class implements the list binding.

Depending on the type of UI component, the list binding may:

Update an attribute of a data object in the bound collection.
Traverse the data objects of the bound collection.
Update a target data object in one collection using the value from another collection's data object.

The list value binding defines its own set of runtime properties.

Range Value Binding

The oracle.jbo.uicli.binding.JUCtrlRangeBinding class implements the range binding.

The range binding permits the databound UI component to obtain a range of attribute values from the specified collection's data objects and to display the position of the current data object relative to that range.

The range value binding defines its own set of runtime properties.

Scroll Value Binding

The oracle.jbo.uicli.binding.JUCtrlScrollBinding class implements the scroll binding.

The scroll binding permits the databound UI component to display the current position of the data object in the selected collection. When the user scrolls the UI component, the scroll binding maintains the current position in the collection.

The scroll value binding defines its own set of runtime properties.

About the Action Binding

The oracle.jbo.uicli.binding.JUCtrlActionBinding class implements the action binding.

The action binding is a type of binding object defined by Oracle ADF that performs actions on the bound data collection&rsquos row set iterator. At runtime, when the user initiates the action, using a button control, the action binding accesses the Oracle ADF binding context and initiates the specified action on the data objects of the selected collection. The action binding supports many predefined actions.

The action binding defines its own set of runtime properties.

For information about how the ADF binding context provides access to these bindings objects at runtime, see About the Oracle ADF Client Binding Context.