Visitor Pattern
The Visitor Pattern is a behavioral design pattern in object-oriented programming that allows you to add further operations to objects without having to modify them. It i used when you have a set of objects with different types, and you want to perfrom a common operation on them without modifying their classes. The pattern achieves this by defining a separate visitor class or interface, which is responsible for performing operations on these objecs. Each object accepts the visitor and delegates the operation to it.
Explanation with Real World Example
Consider a real-world example of a tax calculation system in a finance application:
- Elements (Taxable Items): The elements are different taxable items such as products, services, and investments. Each taxable item is a distinct class with its properties and methods.
- Visitor (Tax Calculator): The visitor, in this case is the tax calculator. It’s a separate class or set of classes responsible for performing tax calculations on various taxable items.
- Operation (Tax Calculation): The operation is the tax calculation itself. It’s a specific operation that needs to be performed on each taxable item. The tax calculator class defines methods for different types of taxable items to calculate taxes.
In this example the Visitor Pattern allows you to add new tax calculation functionality to your finance application without modifying the existing classes of taxable items. Each taxable item can accept the tax calculator (visitor) and delegate the tax calculation operation on it.
The Visitor Pattern used in situations where you have a set of objects with different types or classes and you want to perform a common operation on all of them.
Design Patterns in Object-Oriented Programming (OOP)
Software Development is like putting together a puzzle. Object-oriented programming (OOP) is a popular way to build complex software, but it can be tricky when you face the same design problems repeatedly. That’s where design patterns come in.
Design patterns are like well-known recipes for common problems in software development. They’re not step-by-step instructions, but more like guidelines to help you solve these problems in a flexible and efficient way. These patterns gather the wisdom of the software development community, making it easier for developers to work together and create software that’s easy to maintain, adapt, and reuse.
Important Topics for the Design patterns in object-oriented programming
- Singleton Pattern
- Factory Method Pattern
- Abstract Factory Method Pattern
- Builder Pattern
- Adapter Pattern
- Proxy Pattern
- Decorator Pattern
- Composite Pattern
- Observer Pattern
- Strategy Pattern
- Command Pattern
- State Pattern
- Template Method Pattern
- Visitor Pattern
- Memento Pattern
- Conclusion