How To change the ADF View Object query where-clause at RunTime?

Question

I am trying to create a simple display page which will display user data (username, assoc_dist_id, assoc_agent_id, status , etc). The User data is stored in a database table and i am using an ADF Read Only table based on the View Object to display the data on the JSF page.
However, i want to display only the users that a particular person accessing the page has the AUTH LEVEL to see. e.g. If the person accessing the page is an 'ApplicationAdministrator' then the page should display all users in the table, If its a 'DistributorAdministrator' then the page should display only users associated with that Distributor (i.e. assoc_dist_id = :p_Dist_id ) and If its an 'AgentAdministrator' , then the page should display only users associated with that Agent ( i.e. assoc_agent_id = :p_Agent_id).
Currently my af:table component displays all the users in the table because the query for the view object is (select * from users) . However, i want to use the same viewobject and just set the where-clause at runtime with the appropriate parameter to restrict the dataset returned.
Do anyone knows how to accomplish this ?

Answer 1

David,
See the custom method initializeDynamicVariableDefaults() in the SRViewObjectImpl.java class in the FrameworkExtentions project in the SRDemoSampleADFBC sample application. You can find out how to install the demo if you haven't already from the ADF Learning Center at:
http://www.oracle.com/technology/products/adf/learnadf.html
This class is a framework extension class for view objects that adds a neat, generic feature to be able to dynamic default the value of named bind variables. You can read more about what framework extension classes are and how to use them in Chapter 25, "Advanced Business Components Techniques" of the ADF Developer's Guide for Forms/4GL Developers, also available at the learning center above.
It is an example of generic framework functionality that "kicks in" based on the presence of custom metadata properties on a named bind variable. See section 25.3.3 "Implementing Generic Functionality Driven by Custom Properties" in the dev guide for more details. Using this sample code, if you add a bind variable to a view object, and define a custom metadata property named "DynamicDefaultValue" on that bind variable, and set this custom metadata property to the value "CurrentUser", then that bind variable will have its value dynamically defaulted to the name of the authenticated user logged in. If instead you set this custom property to the value "UserRole", then the bind variable will be set to the comma-separated string containing the list of roles that the authenticated user is part of.
Once you've created a framework extension class for view objects like this, you can have the view objects you create inherit this generic functionality.See section 25.1.4 "How to Base an ADF Component on a Framework Extension Class" in the dev guide for more info on this.
By adapting a technique like this (or some idea similar that better suits your needs) you can have your view object query contain bind variables whose values automatically take on the defaults based on something in the user-session environment.