Thursday, August 9, 2007

Three Dependent List Boxes in af:table Component

You may already have read Frank Nimphius blog post - ADF Faces: How-to create dependent list boxes in a table. Frank describes in his blog how two dependent list boxes can be implemented in af:table component. He implements dependency between Departments and Employees from standard HR schema.

One day I have decided to implement three dependent list boxes in af:table. I thought it will be simple - have applied the same steps as Frank describes and enabled partial triggering on third list based on first and second. However, things aren't always simple - it was not working in such way. But, I have found a solution and implemented it as sample application - DependentListBoxesThree.zip.

Implemented sample application is based on standard HR schema, also the same additional table as in Frank sample is used - VACATIONREQUESTS. However, table is updated with LOCATION_ID column and foreign key is created that references LOCATIONS table. SQL script for table update you will find in application archive.

Sample is based on solution available in Frank blog, so I will describe only those things I have added to make three dependent list boxes work. I have implemented dependency between LOCATIONS, DEPARTMENTS and EMPLOYEES tables from HR schema.

Steps I have applied:

1. In Model layer implement read-only View Object - DepartmentsCheckView. This View Object will be used to check specified department availability in particular location.


2. Open Vacationrequests Entity Object edit window and select Refresh After Insert for Approved attribute.


3. In View layer, for all iterators related to list boxes dependency set StateValidation="false". This will help to avoid JBO-35007 error, this error was generated sometimes for me during sample testing. More information about this error you can find in Chris Muir blog post - Bah! What is JBO-35007.

4. The main problem was to refresh third list box, when second or first list boxes are changed. When second list box is changed, the same solution as for first and second is applied. However, when first is changed, second list changes and third list should appear empty as value in second list is not selected. For this purpose in getEmployeesSelectItems() method checkDepartmentByLocation is invoked. It accepts two parameters - depId and locId and returns 0 or 1. Returned value helps to determine how third list should be generated.


checkDepartmentByLocation method is implemented in Application Module class:


5. List box for employees is created based on EmployeesView2 from DepartmentsView1.


And now will show how it works. Three dependent list boxes:


It is possible to create new row, you can select location, department and employee from list available for selected department. Also notice, that in fourth row I have changed location from Munich to South San Francisco and you can choose department, but can't select employee as no department is currently selected:

When running sample application, don't forget to add adf-faces-impl.jar and jsf-impl.jar to application's WEB-INF\lib directory.

7 comments:

Anonymous said...

Thanks:)

Anonymous said...

Thank's Andrejus

Anonymous said...

Thanks Andrejus for your effort

Ilango said...

Do I have to create Tables in Oracle to run this?
Thank you.

Andrejus Baranovskis said...

Yes, you should create them.

Andrejus

Ilango said...

I downloaded your zip file. How would I set it up in Tomcat? I have copied the required jar files to my tomcat/lib directories.

Andrejus Baranovskis said...

May be this info will help (even it is for 11g): http://blogs.oracle.com/dana/2009/01/how_to_deploy_a_11g_adf_applic_1.html

Regards,
Andrejus