What is Adapter Pattern in Java?
The Adapter Pattern in Java is a design pattern that allows objects with incompatible interfaces to work together. It acts as a bridge between two incompatible interfaces, enabling them to collaborate seamlessly. This pattern is widely used in software development to facilitate the integration of legacy code or third-party libraries into new systems without modifying their existing code.
In Java, the Adapter Pattern is implemented by creating a new class that acts as an adapter between the target interface and the adaptee class. The target interface defines the methods that the client code expects, while the adaptee class provides the actual implementation. The adapter class adapts the adaptee’s interface to match the target interface, allowing the client code to interact with the adaptee class using the target interface.
The Adapter Pattern can be categorized into two types: object adapter and class adapter. The object adapter uses composition to adapt the adaptee class, while the class adapter uses inheritance to adapt the adaptee class.
Here’s an example of the Adapter Pattern in Java:
“`java
// Target interface
interface Target {
void request();
}
// Adaptee class
class Adaptee {
public void specificRequest() {
System.out.println(“Specific request”);
}
}
// Adapter class
class Adapter implements Target {
private Adaptee adaptee;
public Adapter(Adaptee adaptee) {
this.adaptee = adaptee;
}
@Override
public void request() {
adaptee.specificRequest();
}
}
// Client code
public class AdapterPatternDemo {
public static void main(String[] args) {
Target target = new Adapter(new Adaptee());
target.request();
}
}
“`
In this example, the `Target` interface defines the `request()` method that the client code expects. The `Adaptee` class provides the actual implementation of the `specificRequest()` method. The `Adapter` class adapts the `Adaptee` class to match the `Target` interface by implementing the `request()` method and calling the `specificRequest()` method of the `Adaptee` class.
The Adapter Pattern is beneficial in several scenarios:
1. Integrating legacy code or third-party libraries into a new system without modifying their existing code.
2. Facilitating the interaction between classes with incompatible interfaces.
3. Enhancing the flexibility and reusability of the code by decoupling the adaptee and target classes.
By using the Adapter Pattern in Java, developers can create robust and scalable software systems that can easily accommodate changes and integrate various components.
