Adapter Pattern in Java

Adapter Pattern in Java:

// The old class that is already working
class OldCharger {
    void chargeWithTwoPins() {
        System.out.println("Charging with 2 pins...");
    }
}

// The new interface that our system needs to support
interface NewCharger {
    void chargeWithThreePins();
}

// The adapter that converts the old class (OldCharger) to the new interface (NewCharger)
class ChargerAdapter implements NewCharger {
    private OldCharger oldCharger;

    // The old class is passed in the constructor
    public ChargerAdapter(OldCharger oldCharger) {
        this.oldCharger = oldCharger;
    }

    @Override
    public void chargeWithThreePins() {
        System.out.println("Adapter is being used...");
        oldCharger.chargeWithTwoPins(); // The old charger is being used
    }
}

public class AdapterPatternExample {
    public static void main(String[] args) {
        // Old charger object created
        OldCharger oldCharger = new OldCharger();

        // Using the old charger with the new system via the adapter
        NewCharger adapter = new ChargerAdapter(oldCharger);

        // The new system demands a three-pin charger, but we make it possible with the adapter
        adapter.chargeWithThreePins();
    }
}