// Existing way requests are implemented
class OldSystem {
    public void oldRequest() {
        System.out.println("Old System");
    }
}

// New interface
interface NewSystem {
    void newRequest();
}

// Adapter Wrapper class
class Adapter implements NewSystem {
    private OldSystem oldSystem;

    public Adapter(OldSystem oldSystem) {
        this.oldSystem = oldSystem;
    }

    @Override
    public void newRequest() {
        oldSystem.oldRequest();
    }
}

// Using the new system (with adapter)
public class Main {
    public static void main(String[] args) {
        NewSystem newSystem = new Adapter(new OldSystem());
        newSystem.newRequest(); // Outputs: "Old System"
    }
}

import java.util.ArrayList;
import java.util.List;

// Component
interface Employee {
    void showEmployeeDetails();
}

// Leaf
class Developer implements Employee {
    private String name;

    public Developer(String name) {
        this.name = name;
    }

    @Override
    public void showEmployeeDetails() {
        System.out.println("Developer: " + name);
    }
}

// Composite
class Team implements Employee {
    private List<Employee> employeeList = new ArrayList<Employee>();

    @Override
    public void showEmployeeDetails() {
        for(Employee emp:employeeList) {
            emp.showEmployeeDetails();
        }
    }

    public void addEmployee(Employee emp) {
        employeeList.add(emp);
    }
}

// Using composite pattern
public class Main {
    public static void main(String[] args) {
        Employee dev1 = new Developer("John Doe");
        Employee dev2 = new Developer("Jane Doe");

        Team team = new Team();
        team.addEmployee(dev1);
        team.addEmployee(dev2);

        team.showEmployeeDetails();
        // Outputs: "Developer: John Doe", "Developer: Jane Doe"
    }
}

interface Image {
    void display();
}

class RealImage implements Image {
    private String filename;

    public RealImage(String filename) {
        this.filename = filename;
        loadFromDisk();
    }

    private void loadFromDisk() {
        System.out.println("Loading " + filename);
    }

    @Override
    public void display() {
        System.out.println("Displaying " + filename);
    }
}

class ProxyImage implements Image {
    private RealImage realImage;
    private String filename;

    public ProxyImage(String filename) {
        this.filename = filename;
    }

    @Override
    public void display() {
        if (realImage == null) {
            realImage = new RealImage(filename);
        }
        realImage.display();
    }
}

// Using Proxy Pattern
public class Main {
    public static void main(String[] args) {
        Image image = new ProxyImage("test.jpg");

        // Image will be loaded from disk
        image.display();

        // Image will not be loaded from disk
        image.display();
    }
}