Avoiding request scope bean clashes for task flow calls

Question

Hi,
I have two task flows, Tf1 calls Tf2 using a task flow call activity. The structures of the task flows are as follows:
Tf1
  Managed Bean: TfBean, request scope
    class Tf1Bean
      has property goTf2Button
  View: View1
    Button bound to #{TfBean.goTf2Button}
      Action -> task flow call to Tf2
Tf2
  Managed Bean: TfBean, request scope
    class Tf2Bean
      has property testButton
  View: View2
    Button bound to #{TfBean.testButton}
As you can see both have a request scope bean called TfBean but these are different classes in each. The bean classes have different properties for binding the components on the two pages.
When I click the button in View1 to navigate I get an error telling me that class Tf1Bean does not have the property testButton. Clearly Tf2Bean is not being instantiated as TfBean already exists for the request.
I'm guessing this is expected behaviour and it seems logical.
My question however is what would be good standards or practices to avoid this?
One way would be a naming convention, however what if I am consuming Tf2 from a library? In this case it would ideally work as a black box and I should not be concerned about it's implementation, specifically names chosen for internal managed beans. Even if it was not a problem initially, the developer of the task flow could add or change the name of a request scope bean introducing a conflict at a later stage.
Thanks,
Kevin

Answer 1

Hi Frank,
Good to meet you at UKOUG Tech13 yesterday. I changed my test case from request scope to backing bean scope. Unfortunately I still get the same error:
<RichExceptionHandler> <_logUnhandledException> ADF_FACES-60098:Faces lifecycle receives unhandled exceptions in phase RENDER_RESPONSE 6
javax.faces.FacesException: javax.el.PropertyNotFoundException: The class 'yyy.view.Tf1Bean' does not have the property 'testButton'.
  at com.sun.faces.application.ApplicationImpl.createComponentApplyAnnotations(ApplicationImpl.java:1900)
  at com.sun.faces.application.ApplicationImpl.createComponent(ApplicationImpl.java:446)
  at javax.faces.webapp.UIComponentELTag.createComponent(UIComponentELTag.java:222)
  at javax.faces.webapp.UIComponentClassicTagBase.createChild(UIComponentClassicTagBase.java:506)
  at javax.faces.webapp.UIComponentClassicTagBase.findComponent(UIComponentClassicTagBase.java:744)
  at javax.faces.webapp.UIComponentClassicTagBase.doStartTag(UIComponentClassicTagBase.java:1311)
  at org.apache.myfaces.trinidad.webapp.UIXComponentELTag.doStartTag(UIXComponentELTag.java:67)
  at oracle.adfinternal.view.faces.unified.taglib.nav.UnifiedCommandButtonTag.doStartTag(UnifiedCommandButtonTag.java:51)
...etc.
What I think is happening, please correct me if I'm wrong...
Running Tf1, page View1 is displayed.
Clicking the button on View1 initiates a request and an instance of Tf1Bean is instantiated for the managed bean named TfBean.
During the request navigation occurs to Tf2 and hence page View2.
View2 needs a property in TfBean called testButton.
There is already a managed bean instantiated for this request called TfBean, however this is of class Tf1Bean and does not have the property.
I have a simple workspace showing this if you want me to send it to you. I am using 11.1.2.4 by the way.
Thanks,
Kevin