Digging into the Visitor Pattern

In this paper we present an alternative to the VISITOR pattern, DYNAMIC DISPATCHER, that can be applied to extend existing software in a nonintrusive way, and which simulates covariant overriding of visit methods. It allows to express polymorphic operations through visitor classes in a more natural way than the original VISITOR pattern. Our solution DYNAMIC DISPATCHER can be applied without touching existing domain classes. Therefore, it is especially useful to extend frameworks and libraries. We have implemented DYNAMIC DISPATCHER as a small framework in Java and conducted performance measurements which show that the overhead is acceptable in most real world scenarios.

• Type: Conference
• Year: 2004
• Where: SEKE
• Authors: Fabian Büttner, Oliver Radfelder, Arne Lindow, Martin Gogolla
• Keywords: DYNAMIC DISPATCHER, SEKE 2004, Solution Dynamic Dispatcher, VISITOR Pattern