gardener.java

Java程序设计大学教程程序源代码

/**
 * <p>Title: 果园系统</p>
 *
 * <p>Description: 教学演示程序</p>
 * <p>帮助学生理解对象、对象变量、对象引用的概念</p>
 * <p>Copyright: Copyright (c) 2005</p>
 *
 * <p>Company: 刘艺</p>
 *
 * @author 刘艺
 * @version 1.0
 */
package jbookch3.gardensys3;

public class Gardener {
    public static void main(String[] args) {
        Gardener gardensys = new Gardener("张三");
        gardensys.work();
    }

    public Gardener(String name) {
        gardenerName = name;
    }

    public void work() {
        System.out.println(gardenerName + "开始工作");
        plant();
        gain();
    }

    private void plant() {
        System.out.println("——————————————————————————");
        banana = new Fruit();
        banana = null;//banana对象变量引用为空，空对象引用
        if (banana != null)
        { banana.grow();
        banana.harvest();}
        grape = new Fruit("葡萄");
        grape.grow();
        grape.harvest();
        orange = new Fruit("橘子", 3000);
        orange.grow();
        orange.harvest();
        System.out.println("——————————————————————————");
    }

    private void gain() {
        int sum = 0;
        //统计收益
        //sum += banana.gain();//banana对象变量引用为空，空对象引用
        sum += orange.gain();
        sum += grape.gain();
        System.out.println("果园总收益：" + sum);
    }

    private String gardenerName;
    private Fruit banana, grape, orange;
}