>I think you need to use a delegate. Oversimplifing your example (and using C# I'm afraid):

   public class ViewPageClass
>    {
>        public void GetPage()
>        {
>            Parser p = new Parser();
>           // Replace default handling.
>            p.handler = SpecificReplaceWithThisContent;
>            bool b = p.ReplaceWithThisContent();
>        }
>
>        public bool SpecificReplaceWithThisContent()
>        {
>            return false;
>        }
>
>    }
>    public class Parser
>    {
>        public delegate bool Doit();
>
>        public Doit handler;
>
>        public bool ReplaceWithThisContent()
>        {
>            if (handler != null)
>            {
>                return handler();
>            }
>            else
>            {
>                //Do the default handling. E.g:
>                return false;
>            }
>        }
>    }}

So a call to Parser.ReplaceWithThisContent() will actually run the ViewPageClass.SpecificReplaceWithContent()

I think this approach is similar to the one from Denis. Also, later on in this thread, in Message #1475334, I provided the current approach I am using which is simply about making a public method in the client and calling it from the class. Do you see any downsize in that approach?