面试题：Go语言接口设计模式中桥接模式的复杂案例实现

Question

假设要开发一个跨平台图形绘制库，有不同的图形（圆形、矩形）和不同的绘制平台（Windows、Linux）。使用桥接模式设计接口和结构体来实现这种功能，要求代码具备良好的扩展性与解耦性，描述设计过程并提供核心代码。

Answer 1

设计过程

1. 抽象出图形和平台的接口：
   • 创建一个绘制平台的抽象接口，每个具体平台（如Windows、Linux）实现该接口。
   • 创建一个图形的抽象类，包含指向绘制平台接口的指针，并定义绘制图形的抽象方法。每个具体图形（如圆形、矩形）继承该抽象类，并实现绘制方法，调用平台接口的绘制操作。

核心代码（以C++为例）

// 绘制平台接口
class DrawingPlatform {
public:
    virtual void drawCircle(float x, float y, float radius) = 0;
    virtual void drawRectangle(float x1, float y1, float x2, float y2) = 0;
    virtual ~DrawingPlatform() = default;
};

// Windows绘制平台实现
class WindowsDrawingPlatform : public DrawingPlatform {
public:
    void drawCircle(float x, float y, float radius) override {
        // 实际的Windows绘制圆形逻辑
        std::cout << "Windows: Drawing circle at (" << x << ", " << y << ") with radius " << radius << std::endl;
    }
    void drawRectangle(float x1, float y1, float x2, float y2) override {
        // 实际的Windows绘制矩形逻辑
        std::cout << "Windows: Drawing rectangle from (" << x1 << ", " << y1 << ") to (" << x2 << ", " << y2 << ")" << std::endl;
    }
};

// Linux绘制平台实现
class LinuxDrawingPlatform : public DrawingPlatform {
public:
    void drawCircle(float x, float y, float radius) override {
        // 实际的Linux绘制圆形逻辑
        std::cout << "Linux: Drawing circle at (" << x << ", " << y << ") with radius " << radius << std::endl;
    }
    void drawRectangle(float x1, float y1, float x2, float y2) override {
        // 实际的Linux绘制矩形逻辑
        std::cout << "Linux: Drawing rectangle from (" << x1 << ", " << y1 << ") to (" << x2 << ", " << y2 << ")" << std::endl;
    }
};

// 图形抽象类
class Shape {
protected:
    DrawingPlatform* platform;
public:
    Shape(DrawingPlatform* platform) : platform(platform) {}
    virtual void draw() = 0;
    virtual ~Shape() = default;
};

// 圆形类
class Circle : public Shape {
private:
    float x;
    float y;
    float radius;
public:
    Circle(DrawingPlatform* platform, float x, float y, float radius) : Shape(platform), x(x), y(y), radius(radius) {}
    void draw() override {
        platform->drawCircle(x, y, radius);
    }
};

// 矩形类
class Rectangle : public Shape {
private:
    float x1;
    float y1;
    float x2;
    float y2;
public:
    Rectangle(DrawingPlatform* platform, float x1, float y1, float x2, float y2) : Shape(platform), x1(x1), y1(y1), x2(x2), y2(y2) {}
    void draw() override {
        platform->drawRectangle(x1, y1, x2, y2);
    }
};

使用示例

int main() {
    DrawingPlatform* windowsPlatform = new WindowsDrawingPlatform();
    Shape* circleOnWindows = new Circle(windowsPlatform, 100, 100, 50);
    circleOnWindows->draw();

    DrawingPlatform* linuxPlatform = new LinuxDrawingPlatform();
    Shape* rectangleOnLinux = new Rectangle(linuxPlatform, 50, 50, 150, 150);
    rectangleOnLinux->draw();

    delete circleOnWindows;
    delete rectangleOnLinux;
    delete windowsPlatform;
    delete linuxPlatform;

    return 0;
}