Visitor

This is a class diagram example for the Visitor pattern.

Purpose

Allows for one or more operations to be applied to a set of objects at runtime, decoupling the operations from the object structure.

Use When

• An object structure must have many unrelated operations performed upon it.
• The object structure can't change but operations performed on it can.
• Operations must be performed on the concrete classes of an object structure.
• Exposing internal state or operations of the object structure is acceptable.
• Operations should be able to operate on multiple object structures that implement the same interface sets.