Visitor Design Pattern

The Visitor pattern is a behavioral design pattern in object-oriented programming (OOP) that allows adding new operations or behaviors to a group of objects without modifying their class definitions. It enables separating the algorithm or behavior from the objects on which it operates, promoting loose coupling and enhancing maintainability.

The Visitor pattern involves the following key components:

• Visitor: Defines the interface for visiting each element/object in a group. It declares a visit method for each element type, which represents the specific behavior or operation to be performed on that element.

• Concrete Visitor: Implements the Visitor interface and provides the actual implementation of the visit methods for each element type. Each concrete visitor encapsulates a specific behavior or algorithm.

• Element: Defines the interface for the elements that can be visited by a visitor. It declares an accept method that accepts a visitor as an argument.

• Concrete Element: Implements the Element interface and defines the accept method. Each concrete element allows a visitor to visit and perform its specific operation on it.

• Object Structure: Represents a collection or group of elements that can be visited by a visitor. It typically provides methods to manage and access the elements.

By using the Visitor pattern, new operations or behaviors can be added to the elements without modifying their classes. The visitor encapsulates the specific behavior, and the elements accept the visitor, allowing the behavior to be applied dynamically. This pattern is particularly useful when the algorithm or operation varies across different elements, and it helps in avoiding a proliferation of subclasses or modifying existing classes when new operations are needed.