里氏代换原则

java 复制代码

package com.jmj.principles.dmeo2.after;

/**
 * 四边形接口
 */
public interface Quadrilateral {

    double getLength();


    double getWidth();

}

java 复制代码

package com.jmj.principles.dmeo2.after;

/**
 * 长方形类
 */
public class Rectangle implements Quadrilateral{
    private double length;
    private double width;

    public double getWidth() {
        return width;
    }

    public void setWidth(double width) {
        this.width = width;
    }

    public double getLength() {
        return length;
    }

    public void setLength(double length) {
        this.length = length;
    }
}

java 复制代码

package com.jmj.principles.dmeo2.after;



public class RectangleDemo {

    public static void main(String[] args) {
     Rectangle rectangle = new Rectangle();
        rectangle.setLength(20);
        rectangle.setWidth(10);
        resize(rectangle);
        printLengthAndWidth(rectangle);
    }

    //扩宽方法
    public static void  resize(Rectangle rectangle){
        //宽如果比长小，进行扩宽的操作
        while (rectangle.getWidth()<=rectangle.getLength()){
            rectangle.setWidth(rectangle.getWidth()+1);
        }

    }

    public static void printLengthAndWidth(Rectangle rectangle){
        System.out.println(rectangle.getLength());
        System.out.println(rectangle.getWidth());
    }

}

java 复制代码

package com.jmj.principles.dmeo2.after;

import com.jmj.principles.dmeo2.before.Rectangle;

/**
 * 正方形
 */
public class Square implements Quadrilateral {

    private double side;

    public double getSide() {
        return side;
    }

    public void setSide(double side) {
        this.side = side;
    }

    @Override
    public double getLength() {
        return side;
    }

    @Override
    public double getWidth() {
        return side;
    }
}