Copy or Clone a Class

I am trying something out with the Prototype design pattern, which involves cloning one object from another. In C++ you have copy constructors and in Java a Clone method that do the basic cloning work. I am fairly sure I don't see an equivalent built-in feature in ABAP Objects. Is anyone aware of a good template or example for writing a cloning method? (Note: some if the interfaces in the ixml library, for example, if_ixml_stream, have a clone method, but I can't find any implementing classes.)