【设计模式】用Java实现桥接模式

// 抽象部分 - 形状
abstract class Shape {
    protected DrawingAPI drawingAPI;
    public Shape(DrawingAPI drawingAPI) {
        this.drawingAPI = drawingAPI;
    }
    public abstract void draw();
}
// 实现部分 - 绘图API
interface DrawingAPI {
    void drawCircle(double x, double y, double radius);
}
// 具体实现部分A - 绿色圆形
class GreenCircle implements DrawingAPI {
    public void drawCircle(double x, double y, double radius) {
        System.out.printf("Drawing green circle at (%.1f, %.1f) with radius %.1f%n", x, y, radius);
    }
}
// 具体实现部分B - 红色圆形
class RedCircle implements DrawingAPI {
    public void drawCircle(double x, double y, double radius) {
        System.out.printf("Drawing red circle at (%.1f, %.1f) with radius %.1f%n", x, y, radius);
    }
}
// 扩展抽象部分 - 圆形
class Circle extends Shape {
    private double x, y, radius;
    public Circle(double x, double y, double radius, DrawingAPI drawingAPI) {
        super(drawingAPI);
        this.x = x;
        this.y = y;
        this.radius = radius;
    }
    public void draw() {
        drawingAPI.drawCircle(x, y, radius);
    }
}
// 使用示例
public class Main {
    public static void main(String[] args) {
        DrawingAPI greenAPI = new GreenCircle();
        Shape greenCircle = new Circle(100, 100, 50, greenAPI);
        greenCircle.draw();
        DrawingAPI redAPI = new RedCircle();
        Shape redCircle = new Circle(200, 200, 100, redAPI);
        redCircle.draw();
    }
}

// 抽象部分 - 用户
abstract class User {
    protected PaymentGateway paymentGateway;
    public User(PaymentGateway paymentGateway) {
        this.paymentGateway = paymentGateway;
    }
    public abstract void purchase(double amount);
}
// 实现部分 - 支付网关
interface PaymentGateway {
    void processPayment(double amount);
}
// 具体实现部分A - 支付宝支付
class Alipay implements PaymentGateway {
    public void processPayment(double amount) {
        System.out.println("Processing payment via Alipay: $" + amount);
    }
}
// 具体实现部分B - 微信支付
class WeChatPay implements PaymentGateway {
    public void processPayment(double amount) {
        System.out.println("Processing payment via WeChat Pay: $" + amount);
    }
}
// 扩展抽象部分 - 会员用户
class PremiumUser extends User {
    public PremiumUser(PaymentGateway paymentGateway) {
        super(paymentGateway);
    }
    public void purchase(double amount) {
        System.out.println("Premium user is making a purchase...");
        paymentGateway.processPayment(amount * 0.9); // 享受9折优惠
    }
}
// 扩展抽象部分 - 普通用户
class RegularUser extends User {
    public RegularUser(PaymentGateway paymentGateway) {
        super(paymentGateway);
    }
    public void purchase(double amount) {
        System.out.println("Regular user is making a purchase...");
        paymentGateway.processPayment(amount);
    }
}
// 使用示例
public class Main {
    public static void main(String[] args) {
        PaymentGateway alipay = new Alipay();
        PaymentGateway weChatPay = new WeChatPay();
        User premiumUser = new PremiumUser(alipay);
        premiumUser.purchase(100);
        User regularUser = new RegularUser(weChatPay);
        regularUser.purchase(50);
    }
}