Understanding the Adapter Pattern in Java

The Adapter Pattern is a structural design pattern that allows incompatible interfaces to work together. It acts as a bridge between two incompatible interfaces by converting the interface of a class into another interface that a client expects. This pattern involves a single class called Adapter, which is responsible for joining functionalities of independent or incompatible interfaces.

Let’s create a simple example using Java to illustrate the Adapter Pattern.

Step 1: Define Target Interface

Step 2: Create Adaptee Class

Step 3: Implement Adapter Class

Step 4: Client Code

Explanation:

• Target is the interface that the client code expects. In this case, it has a request method.
• Adaptee is the class with the specific functionality that we want to adapt. It has a specificRequest method.
• Adapter is the class that implements the Target interface and contains an instance of Adaptee. It delegates the request method to the specificRequest method of Adaptee.
• In the client code, we create an instance of Adaptee, then create an instance of Adapter and pass the Adaptee instance to it. Finally, we call the request method of the Target interface (via the Adapter).

When you run the Client class, it will output:

Specific request from Adaptee

This demonstrates how the Adapter Pattern allows the client code to work with the Target interface while utilizing the functionality of the Adaptee class. The adapter acts as a bridge between the two interfaces.