Adapter Design Pattern in C#

Adapter Design Pattern :

Adapter is a structural design pattern that allows objects with incompatible interfaces to collaborate.

Analogy :

Imagine you have different electronic devices with various power plugs, and you want to connect them all to a single power outlet.

Instead of modifying the devices, you use plug adapters. These adapters act as intermediaries, allowing each device to connect to the outlet seamlessly.

Similarly, the Adapter Design Pattern lets incompatible classes work together by providing a wrapper (adapter) that bridges the gap between their interfaces.

When should we use it ?

Utilize the Adapter class when you need to incorporate an existing class into your code, but its interface doesn’t align with the rest of your system.

Advantages and Disadvantages By using adapter design pattern we fulfill S and O from SOLID Principles , although in some situations it can increase the complexity of code.

Enough talk, let’s see code in action.

How to implement Adapter in C#

Suppose we have some old code with in compatible interfaces.

public sealed class OldSystem
{
    public void DoSomethingOld()
    {
        Console.WriteLine("Doing something the old way.");
    }
}

And now we have a new interface expected by the rest of the code

public interface INewSystem
{
    void DoSomethingNew();
}

Let’s make an adapter class that makes OldSystem compatible with INewSystem

 public class Adapter : INewSystem
{
    private OldSystem _oldSystem;

    public Adapter(OldSystem oldSystem)
    {
        _oldSystem = oldSystem;
    }

    public void DoSomethingNew()
    {
        _oldSystem.DoSomethingOld();
    }
}

Let’s see now how can we utilise it.

class Program
{
    static void Main()
    {
        OldSystem oldSystem = new OldSystem();
        INewSystem adaptedSystem = new Adapter(oldSystem);
        adaptedSystem.DoSomethingNew();
    }
}

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Adapter Design Pattern in C#