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📐 DESIGN PATTERN: Visitor

July 14, 2024

The ____ Pattern is a design pattern that lets you add new operations to objects without changing their class structures.

It separates the algorithm from the objects and enables dynamic dispatch of operations based on object types.

* Mediator

* Interpreter

* Visitor

* Observer

#programming #design #pattern

 

Answer: Visitor

The Visitor Pattern is a behavioral design pattern in software development that allows you to add new operations to objects without changing their class structures. It achieves this by separating the algorithm (visitor) from the objects on which it operates, enabling dynamic dispatch of the operation based on the object's type.

Visitor:

The Visitor is an interface or abstract class that defines a set of visit methods, each corresponding to a different type of object. Concrete visitor classes implement these methods to perform specific operations on objects.

Element:

The Element is an interface or abstract class that declares an accept method.

Concrete element classes implement this method and accept a visitor as an argument.

The accept method dispatches the visit operation to the appropriate visitor method.

Concrete Visitor:

Concrete Visitor classes are specific implementations of the visitor interface.

Each concrete visitor provides the logic for the visit methods associated with different element types.

Concrete Element:

Concrete Element classes are specific implementations of the element interface.

They implement the accept method to call the appropriate visitor's visit method.

Object Structure:

The Object Structure represents a collection of elements and provides methods for adding, removing, or iterating over them.

It's the entry point for initiating visitor operations on its elements.

The Visitor Pattern is beneficial in scenarios where you need to add new operations or behaviors to a set of objects without modifying their class hierarchy.

It promotes maintainability, extensibility, and the ability to work with complex object structures.

It's commonly used in compilers, abstract syntax trees, and various data processing applications.