package edu.mama.ls18.homework;
    /*
     乌龟
    */
    _public class TortoiseRunnable implements Runnable{
    private Race race;
    public TortoiseRunnable(Race race) {
    if (race == null) {
    throw new IllegalArgumentException(“race不能为null”);
    }
    this.race = race;
    }
    @Override
    public void run() {
    while(race.isPlaying){
    race.tortoiseDistance+=1;
    System._out    .println(“乌龟：爬”);
    try {
    Thread.sleep(1000);
    } catch (InterruptedException e) {
    e.printStackTrace();
    }
    }
    }
    }