Common Design Patterns Uses in .Net World

 

Common Design Patterns

1.      Singleton Pattern:

• Scenario: In a logging service for an e-commerce platform, you want to ensure that there is only one instance of the logger throughout the application to maintain consistent logging behavior and manage resources efficiently.

2.      Factory Pattern:

• Scenario: A payment processing system needs to create different types of payment gateways (e.g., PayPal, CreditCard) based on user preferences. Using a factory pattern, you can encapsulate the logic for creating these objects and provide a uniform interface to interact with them.

3.      Builder Pattern:

• Scenario: You're developing a report generation module where reports can have different formats (e.g., PDF, Excel). The builder pattern allows you to construct complex report objects step by step and produce different representations of the final report without exposing its internal construction.

4.      Adapter Pattern:

• Scenario: Integrating a legacy CRM system that uses its own interface with a new customer management module in your application. You can create an adapter that translates calls between the new module's interface and the legacy CRM system's interface, ensuring seamless integration.

5.      Decorator Pattern:

• Scenario: Adding optional features (e.g., encryption, compression) to data streams in a file transfer application. Using decorators, you can dynamically attach these features to data streams without modifying the base classes of data transfer components.

6.      Observer Pattern:

• Scenario: A stock market application where multiple investors want to receive real-time updates on stock prices. The observer pattern allows the investors (observers) to subscribe to updates from the stock market (subject), ensuring that they are notified whenever there is a change in stock prices.

7.      Strategy Pattern:

• Scenario: A shipping cost calculation system where different shipping carriers (e.g., FedEx, UPS) have different algorithms for calculating shipping costs based on package size, weight, and delivery location. Using the strategy pattern, you can encapsulate each algorithm and dynamically switch between them based on user preferences or business rules.

8.      Template Method Pattern:

• Scenario: Implementing a workflow engine for processing customer orders, where each order follows a predefined sequence of steps (e.g., validate order, process payment, ship items). The template method pattern defines the overall order processing workflow in a base class, with specific steps implemented in subclasses based on the type of order.

9.      Facade Pattern:

• Scenario: Developing a customer support portal where support agents need to access various backend systems (e.g., CRM, billing, inventory) to assist customers. The facade pattern provides a simplified interface (facade) that aggregates the complex interactions with these systems, making it easier for support agents to perform their tasks without directly dealing with the intricacies of each backend system.

10.  Iterator Pattern:

• Scenario: Implementing a collection of customer records in a CRM application, where you need to iterate over the records to perform operations such as searching, sorting, or displaying them in different views. The iterator pattern provides a standardized way to traverse the elements of the collection without exposing its underlying structure, ensuring flexibility in how you access and manipulate customer data.