Using Visitor Patterns on non Visitable Structures

The visitor pattern can be used on structures of objects which implements a specific interface defining a method called accept. In practice, in many cases, the structures are already created and we have to visit structures of already created objects. Changing hierarchies of classes for adding a new method is not a viable solution.

We need somehow to extend the structure of objects for accepting the visitors without changing them. A way of doing it would be to add a wrapper for the hierarchy classes which accepts visitors and duplicates the structure.

Did you enjoy this tutorial? Be sure to subscribe to the my RSS feed not to miss my new posts!
... or make it popular on

Leave a Comment.