Visitor Pattern
The Visitor Pattern is a behavioral design pattern in object-oriented programming that allows you to separate algorithms from the objects on which they operate. It enables adding new operations to existing object structures without modifying those structures, by defining a visitor class that implements operations for each element type. This pattern is particularly useful for performing operations across a set of objects with different interfaces.
Developers should use the Visitor Pattern when they need to perform many unrelated operations on a complex object structure, such as in compilers for syntax tree traversal, document processing, or UI rendering. It's ideal when the object structure is stable but operations may change or expand, as it avoids polluting element classes with unrelated methods and adheres to the open/closed principle.