Data Structures and Algorithms
with Object-Oriented Design Patterns in Java 
A visitor represents an operation to be performed on all the objects within a container. All visitors share a common interface, and thereby hide the operation to be performed from the container. At the same time, visitors are defined separately from containers. Thus, a particular visitor can be used with any container.
Copyright © 1998 by Bruno R. Preiss, P.Eng. All rights reserved.