29 Apr 2012

Get access to the BackingBeanScope of the inner TaskFlow

Let's say we have a page with a region and some bounded task flow inside the region. The task flow has some backingBean scope managed bean:

 <managed-bean id="__1">
  <managed-bean-name id="__2">BackBean</managed-bean-name>
  <managed-bean-class id="__3">view.BackBean</managed-bean-class>
  <managed-bean-scope id="__4">backingBean</managed-bean-scope>
 </managed-bean>

We need to have an access to this bean outside of the task flow. For example we need to disable a button on the main page depending on some property of the BackBean.  We can do the following:

  // taskflow is <taskFlow id="taskflowdefinition1" from our pageDef
  public Map getBackingBeanScope4TaskFlow(String taskflow) 
  {
    Map resultMap = null;
    
    //We need the full name of our taskflow
    DCBindingContainer dcb =
        (DCBindingContainer)BindingContext.getCurrent().getCurrentBindingsEntry();
    DCTaskFlowBinding dfb = (DCTaskFlowBinding) dcb.findExecutableBinding(taskflow);
    String fullName = dfb.getFullName();                                 
  
    //Get the provider
    BackingBeanScopeProviderImpl bbProvider =
            ((BackingBeanScopeProviderImpl)AdfFacesContext.getCurrentInstance().getBackingBeanScopeProvider());
    
    //Left parenthesis
    bbProvider.begin(fullName);
    
    //Now the current backing bean scope is the scope of our task flow
    try {
       resultMap = bbProvider.getCurrentScope();
    } finally {
    //Right parenthesis
        bbProvider.end();
    }
    
    return resultMap; 
  }

  public Object getBackBean() 
  {
    return getBackingBeanScope4TaskFlow("taskflowdefinition1").get("BackBean"); 
  }
  

 Of-course using this technique is a little bit against the encapsulation concept - we should not have access to the details of the inner/child objects. We have to be aware of that. And for our use-case it'd be probably better to use contextual events or something else. But in any case we know how to do the trick, and Knowledge is Power :).

That's it!

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