Binding the Data - Oracle ADF 11gR2 Development Beginner's Guide - page 122

ADF model layer
The ADF model layer is the architectural element that will allow the UI layer to interact with
the data layer. The model layer is responsible for providing the key business services that
are available in the view layer. The informaion is bound to the UI component with the help
of the bindings deined in the page deiniion ile. The PageDef file that is created for each
ADF bound view holds the binding deiniion for the view's UI components to query data
from the business service. The following screenshot explains the relaionship between the
UI page and the page deiniion ile. Here we can see that the Empno column in the UI is
mapped to the Empno atribute exposed from the EmpVO1 enity through the Data controls
pane. The table data displayed in the UI uses the collecion model of the EmpVO1 collecion
binding. Collection Model is the object that holds the collecion of rows returned from
the VO query in the row set. The binding will make use of the EmpVO1Iterator module in
the executable secion to iterate the data from the EmpVO1 collecion from the data control
palete. The data control layer is populated using the data control layer usage informaion
defined in the DataBindings.cpx file.
In our EmpDirectoryApplication applicaion, we have dragged and dropped the
EmpVO1 instance from the Data Controls panel to the index.jspx page to display the
data them the EMP table. The table component is ied up to the EmpVOIterator module
of the page deiniion ile to collect the data to display in the UI layer. The tree binding
EmpVO1 of the indexPageDef.xml file uses the EmpVO1Iterator executable to
display the data exposed through the data control layer. In our previous chapter, we have
exposed the getHelloWorld() operaion from the application module to display
the informaion in the UI page. There are other built-in operaions, such as commit and
rollback from the application module, that can be exposed through the data control
layer using the ADF model bindings. These built-in operaions are not exposed in the
previous secion of the screenshot.