Java实现(07)——桥接模式(Bridge Pattern)

桥接模式用于连接两个不相干的抽象实现，这种模式中存在一个当做桥梁的接口，本例展示可以用不同的颜色画一个圆，但是提供相同的抽象接口。

public interface DrawAPI {
    public void drawCircle(int radius, int x, int y);
}

public class RedCircle  implements DrawAPI {

    @Override
    public void drawCircle(int radius, int x, int y) {
        System.out.println("Drawing Circle[ color: red, radius: " + radius + ", x: " + x + ", " + y + "]");
    }
}

public class GreenCircle implements DrawAPI {
    @Override
    public void drawCircle(int radius, int x, int y) {
        System.out.println("Drawing Circle[ color: green, radius: " + radius + ", x: " + ", " + y + "]");
    }
}

public abstract class Shape {
    protected DrawAPI drawAPI;
    protected Shape(DrawAPI drawAPI) {
        this.drawAPI = drawAPI;
    }
    public abstract void draw();
}

public class Circle extends Shape {
    private int x, y, radius;
    public Circle(int x, int y, int radius, DrawAPI drawAPI) {
        super(drawAPI);
        this.x = x;
        this.y = y;
        this.radius = radius;
    }
    @Override
    public void draw() {
        drawAPI.drawCircle(radius, x, y);
    }
}

public class Demo {
    public static void main(String[] args) {
        Shape redCircle = new Circle(100,100, 10, new RedCircle());
        Shape greenCircle = new Circle(100, 100, 10, new GreenCircle());
        redCircle.draw();
        greenCircle.draw();
    }
}

输出：

Drawing Circle[ color: red, radius: 10, x: 100, 100]
Drawing Circle[ color: green, radius: 10, x: , 100]