Bridge

Context: Decouple an abstraction from its implementation so that the two can vary independently.

public interface IImplementation
{
    void OperationImpl();
}

public class ConcreteImplA : IImplementation
{
    public void OperationImpl() => Console.WriteLine("Impl A");
}

public abstract class Abstraction
{
    protected IImplementation _impl;
    protected Abstraction(IImplementation impl) => _impl = impl;
    public abstract void Operation();
}

public class RefinedAbstraction : Abstraction
{
    public RefinedAbstraction(IImplementation impl) : base(impl) { }
    public override void Operation() => _impl.OperationImpl();
}

Real-world usage example

Device drivers and remote controls: A remote control abstraction can work with different device implementations (TV, radio, projector). Adding a new remote (e.g., voice remote) doesn’t affect device classes.

Example: In .NET, Stream is an abstraction; FileStream, MemoryStream are implementations. GZipStream is another abstraction that uses a stream implementation – bridge pattern.

Bridge

Real-world usage example

Related sections