Oracle Magazine - September/October 2007 - Marcelo Machado

FRAMEWORKS
FRAMEWORKS
the two lists of values. In Oracle
ADF 11g, you can configure a list
of values as a declarative feature
of any view object attribute. By
defining the list of values at the
model layer instead of within
the user interface (UI), you can
ensure that your UI will present a
list of values correctly and consistently,
regardless of the particular
Oracle ADF–supported UI client
technology you decide to use.
In the Application Navigator,
begin by double-clicking
EmpView to open the view
object editor. Note that in Oracle
JDeveloper 11g, the business component
editors appear as tabs within the
main editor area instead of in a modal
dialog box. Select the Attributes category
along the left edge of the editor
page, and select the Deptno attribute in
the table that appears in the Attributes
section near the top of the editor frame.
Find the List of Values: Deptno section
header below, and click the green plussign
icon on the right side of the header
to create a list of values for the Deptno
attribute. When the List of Values dialog
box appears, click the green plus-sign
icon in the List Data Source section to
add a datasource that will supply the
list of valid choices for this attribute’s
value. In the View Accessors dialog box
that appears, select the DeptView view
object in the Available View Objects list
on the left and click the Add Instance
(right-arrow) button to add a new
view accessor named DeptView1 for the
selected view object. Then click OK.
Note that the newly added view accessor
datasource DeptView1 appears in the
List Data Source tree display in the List of
Values dialog box. Expand it, and select
its Deptno attribute. Note that the List
Return Values section updates to show
how attributes in the list datasource will
be assigned to attributes in the base view
object when the user makes a choice
from the list. You won’t need to modify
this section for this example, but note
that you could map additional return
value attributes in your application by
adding to this list.
Before leaving the List of Values dialog
Figure 1: Testing view object with cascading lists of values
box, click the Edit List UI Hints...
button (near the top of the window) to
open the List UI Hints dialog box. These
settings provide information that defines
how the list should appear within the
user interface. Note that the default
list type indicates a Choice List display
style. You will use this default list type
for this simple example, but if you click
the list, you’ll see the other types of list
controls you can use within your own
applications. In the Display Attributes
section, select the Dname attribute from
the Available list and click the Add
(right-arrow) button to add it to the
list of selected attributes. This selection
indicates that you want the user to see
the department name, rather than the
department number, in the list. Finally,
click OK to close the List UI Hints
dialog box and OK again to close the
List of Values dialog box.
Next, let’s configure the list of values
for the Mgr attribute. As before, select
this attribute in the Attributes section of
the view object editor for the EmpView
object. Then click the green plus-sign
icon in the List of Values: Mgr section
header. When the List of Values dialog
box appears, click the green plus-sign
icon in the List Data Source section to
add a new datasource that will supply
the list of valid choices for this attribute’s
value. In the View Accessors dialog box,
select the ManagerListForDepartment
view object from the Available View
Objects list on the left and click the
Add Instance (right-arrow) button to
add a new view accessor named
64 SEPTEMBER/OCTOBER 2007 ORACLE.COM/ORACLEMAGAZINE
ManagerListForDepartment1 for the
selected view object.
Because this view object has
bind variables, you need to configure
how those bind values will get
their values. To do so, make sure
the ManagerListForDepartment1
view accessor is selected and click
the Edit button. In the Edit View
Accessor dialog box, note that the
bind variable names CurrentDept
and CurrentEmp appear in the Bind
Parameter Values section. Check
the Row-level bind values exist
check box and double-click the
Value column for the CurrentEmp
bind variable in the table. You want to
assign the value of this bind variable
to be the value of the Empno attribute
in the current row, so enter the (casesensitive)
expression Empno in this cell.
Similarly, double-click the value column
for the CurrentDept bind variable, and
enter the expression Deptno to assign
this bind variable’s value to the value of
the Deptno attribute in the current row.
Finally, click OK to close the Edit View
Accessor dialog box and OK again to
close the View Accessors dialog box. In
the List of Values dialog box, expand
ManagerListForDepartment1 in the List
Data Source tree and select its Empno
attribute. Then, click Edit UI Hints as
before to configure Ename as the list’s
display attribute. Click OK to close the
List UI Hints dialog box and OK again to
close the List of Values dialog box.
TESTING YOUR LISTS OF VALUES
You can use the enhanced Oracle
ADF 11g Oracle Business Component
Browser to immediately test the LOVs
you’ve just configured. To run the
application module in the Oracle
Business Component Browser, rightclick
the HRModule component in the
Application Navigator and select Run.
After you click Connect in the dialog
box that appears, the Oracle Business
Component Browser will appear.
Double-click the EmpView1 view object
instance to see its data. As shown in
Figure 1, both Mgr and Deptno appear
as lists. If you select the Mgr list, you’ll
notice that the list includes the employ-