How can we mandatory the attachment in OAF Page?

We can mandatory the attachment in OAF page thorugh CO extension by follow these easy steps -

Step 1) We have to find the right controller to extend.

Step 2) Inside ProcessFormRequest of that controller we should catch the id of Submit button by -

            if (pageContext.getParameter("SubmitButtonID")!=null

Step 3) We should catch the id of FileUploadBean by -

        OAMessageFileUploadBean UploadBean=    (OAMessageFileUploadBean)webBean.findIndexedChildRecursive("UploadBeanID");
       
        pageContext.writeDiagnostics(this,"Check if upload bean is not null"+UploadBean,1);    
   
Step 4) Now we have to find that is there any value in UploadBean or not, if there is value that mean the file is attached.

        String val = (String)UploadBean.getValue(pageContext);

        pageContext.writeDiagnostics(this,"value of val is :"+val,1);

Step 5) Raise the error if file is not attached -

             if (val == null)
           {
           
    throw new OAException ("Please attach a file !!! ",OAException.ERROR);

           }