How to get the application module instance in backing bean.

Question

This is Ramesh, I am new to JDeveloper world.
In my current application I have change password screen which allows user to change there password.
Here this is a pop-up page. Here I don't have the view object and pagadef for this changepassword.jspx file.
My aim is to call the Application Module method which takes the user name, old password and new password.
In backing bean I am trying to call this method by using
MyProjAM obj = _binding.getDataControl().getApplicationModule();  //throw null pointer exception.
_binding is the object of DCBindingContainer. 
( I have created the parameter called "binding" as my managed bean property and values as #{binding})
But the above line is throwing the NullPointerException.
Could you please help me to come out of this problem.
Thanks and Regards,
Ramesh Biradar.

Answer 1

If your page has no page definition, then #{bindings} will be null during the request for that page.
If you need your page to invoke a data control method when you press a button, the simplest (and declarative) way is publish your AM method on the AM's client interface, then drop the method as a button from the data control palette onto your page. You don't even need a backing bean to accomplish this.
That said, you can refer to a data control in a backing bean using the expression #{data.[i]YourAppModuleNameDataControl.dataProvider}
So, assuming you have a helper method like this:
  public static Object EL(String expression) {
    FacesContext ctx = getFacesContext();
    Application app = ctx.getApplication();
    ValueBinding bind = app.createValueBinding(expression);
    return bind.getValue(ctx);
  }and assuming that your application module is named SRService
and assuming that you have correctly nominated any Application Module custom methods as being available to clients by selecting them on the "Client Interface" panel of the application module editor, then in a backing bean you can acquire an instance.
Then, the ADF design time will have automatically generated you a custom AM client interface named SRService and you can reference that service interface in your backing bean by using code like this:
        SRService svc = (SRService)EL("#{data.SRService.dataProvider}");
        svc.yourCustomMethod(your,args);