How do you deal with incompatible interfaces when using the adapter pattern?

3 How to apply the adapter pattern?

To apply the adapter pattern, you need to identify four roles: the target, the client, the adaptee, and the adapter. The adapter can be implemented in two ways - class adapter and object adapter. The class adapter uses inheritance to extend the adaptee and implement the target interface, while the object adapter uses composition to hold a reference to the adaptee and implement the target interface.

4 How to model the adapter pattern with UML?

The adapter pattern can be modeled with UML class diagrams that show the relationships between the classes involved. Here is an example of a class diagram for the object adapter:

[Image: A UML class diagram for the object adapter pattern. It shows four classes: Target, Adapter, Adaptee, and Client. Target has an operation called request(). Adapter implements Target and has an attribute called adaptee of type Adaptee. Adapter also has an operation called request() that calls adaptee.specificRequest(). Adaptee has an operation called specificRequest(). Client uses Target to invoke request().]

The class diagram for the class adapter is similar, except that Adapter inherits from both Target and Adaptee, instead of having an attribute of type Adaptee.

5 How to implement the adapter pattern with code?

The adapter pattern can be implemented with any programming language that supports inheritance or composition. Here is an example of a Java code for the object adapter:

// The target interface

public interface Target {

void request();

}

// The adaptee class

public class Adaptee {

public void specificRequest() {

System.out.println("Adaptee: Doing something specific");

}

}

// The adapter class

public class Adapter implements Target {

private Adaptee adaptee;

// Constructor that takes an adaptee as an argument

public Adapter(Adaptee adaptee) {

this.adaptee = adaptee;

}

// Implement the target interface by delegating to the adaptee

public void request() {

System.out.println("Adapter: Converting request");

adaptee.specificRequest();

}

}

// The client class

public class Client {

public static void main(String[] args) {

// Create an adaptee object

Adaptee adaptee = new Adaptee();

// Create an adapter object that wraps the adaptee

Target target = new Adapter(adaptee);

// Use the target interface to invoke the request

target.request();

}

}