Understanding the Adapter Design Pattern in C#

Bridging incompatible interfaces with the power of design the Adapter Pattern in C#

In modern software development, we often encounter situations where two incompatible interfaces need to work together. The Adapter Design Pattern provides a solution for this by acting as a bridge between these incompatible interfaces. It is widely used in C# and other object-oriented languages to enhance code flexibility and maintainability.

What is the Adapter Design Pattern?

The Adapter Pattern is a structural design pattern that allows objects with incompatible interfaces to collaborate. Essentially, it converts the interface of a class into another interface that the client expects.

• Purpose: Allow incompatible interfaces to work together without changing their source code.

• Also Known As: Wrapper.

• Category: Structural pattern.

When to Use the Adapter Pattern

Use the Adapter Pattern when:

1. You want to integrate a class with an existing system but its interface is incompatible.

2. You want to reuse an existing class but need to adapt it to a new interface.

3. You aim to decouple code and make it more flexible and maintainable.

Structure of Adapter Pattern

The Adapter Pattern generally involves the following components:

1. Target – Defines the domain-specific interface that the client uses.

2. Client – Collaborates with objects conforming to the Target interface.

3. Adaptee – The existing class with an incompatible interface.

4. Adapter – Converts the interface of the Adaptee into the Target interface expected by the Client.

Client → Target → Adapter → Adaptee

C# Example of Adapter Pattern

Imagine we have an old legacy logging system and a new system that expects a different interface.

Step 1: Define the Target Interface

public interface ILogger
{
    void Log(string message);
}

Step 2: Existing Class (Adaptee)

public class LegacyLogger
{
    public void WriteLog(string logMessage)
    {
        Console.WriteLine($”Legacy log: {logMessage}”);
    }
}

Step 3: Create the Adapter

public class LoggerAdapter : ILogger
{
    private readonly LegacyLogger _legacyLogger;

    public LoggerAdapter(LegacyLogger legacyLogger)
    {
        _legacyLogger = legacyLogger;
    }

    public void Log(string message)
    {
        _legacyLogger.WriteLog(message); // Adapted call
    }
}

Step 4: Using the Adapter

class Program
{
    static void Main(string[] args)
    {
        LegacyLogger legacyLogger = new LegacyLogger();
        ILogger logger = new LoggerAdapter(legacyLogger);

        logger.Log(”Adapter pattern in action!”);
    }
}

Output:

Legacy log: Adapter pattern in action!

Here, the LoggerAdapter bridges the gap between the ILogger interface and the LegacyLogger class.

Benefits of Adapter Pattern

• Promotes code reuse without modifying existing code.

• Enhances flexibility by decoupling client code from specific implementations.

• Makes it easier to integrate third-party libraries.

Real-World Examples

1. Connecting new payment gateways to legacy e-commerce systems.

2. Adapting different file format readers in a document management system.

3. Bridging old APIs with modern service-oriented architectures.

Conclusion

The Adapter Design Pattern is a simple yet powerful solution to interface incompatibility problems. By using it in C#, you can integrate legacy systems, third-party libraries, or any incompatible components seamlessly while keeping your code clean and maintainable.

💬 Have you ever used the Adapter Pattern in a real project? What challenges did it help you solve?

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👉 Full working code available at:

🔗https://sourcecode.kanaiyakatarmal.com/AdapterDesignPattern

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I hope you found this guide helpful and informative.

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