简答题) 一、程序填空题：搭建流水线 1.相关知识点： 如果对象a含有对象b的引用，对象b含有对象c的引用，那么就可以使用a、b、c搭建流水线。流水线的作用是，用只需将要处理的数据交给流水线，流水线会依次让流水线上的对象来处理数据，即流水线上首先由对象a处理数据，a处理数据后，自动将处理的数据交给b，b处理数据后，自动将处理的数据交给c。 2.实验目的 让学生掌握怎样搭建符合特殊用途的链式结构数据。 3.实验要求 程序有时候需要将任务按流水式进行，例如评判体操选手的任务按流水式为依次的三个步骤：录入裁判给选手的分数，去掉一个最高分和一个最低分，计算出平均成绩。 编写程序，搭建流水线，只需将评判体操选手的任务交给流水线即可。 源程序见附件，测试类为GymnasticGame，请补充各个类中缺失的代码。

1. Score类

public class Score {
    private double score;

    public Score(double score) {
        this.score = score;
    }

    public double getScore() {
        return score;
    }
}

2. Handler类

public abstract class Handler {
    protected Handler successor;

    public void setSuccessor(Handler successor) {
        this.successor = successor;
    }

    public abstract void handleRequest(Score score);
}

3. RemoveHighestScore类

public class RemoveHighestScore extends Handler {
    @Override
    public void handleRequest(Score score) {
        double[] scores = {score.getScore(), successor.getNextScore().getScore(), successor.getNextScore().getNextScore().getScore()};
        Arrays.sort(scores);
        score = new Score(scores[1]);
        successor.handleRequest(score);
    }

    public Score getNextScore() {
        return successor.getNextScore();
    }
}

4. RemoveLowestScore类

public class RemoveLowestScore extends Handler {
    @Override
    public void handleRequest(Score score) {
        double[] scores = {score.getScore(), successor.getNextScore().getScore(), successor.getNextScore().getNextScore().getScore()};
        Arrays.sort(scores);
        score = new Score(scores[1]);
        successor.handleRequest(score);
    }

    public Score getNextScore() {
        return successor.getNextScore();
    }
}

5. CalculateAverageScore类

public class CalculateAverageScore extends Handler {
    @Override
    public void handleRequest(Score score) {
        double sum = score.getScore() + successor.getNextScore().getScore() + successor.getNextScore().getNextScore().getScore();
        double average = sum / 3;
        System.out.println("选手的平均成绩为：" + average);
    }
}

6. GymnasticGame类

public class GymnasticGame {
    private Handler handler;

    public void setHandler(Handler handler) {
        this.handler = handler;
    }

    public void handleRequest(Score score) {
        handler.handleRequest(score);
    }

    public static void main(String[] args) {
        Score score1 = new Score(9.5);
        Score score2 = new Score(9.8);
        Score score3 = new Score(9.3);

        RemoveHighestScore removeHighestScore = new RemoveHighestScore();
        RemoveLowestScore removeLowestScore = new RemoveLowestScore();
        CalculateAverageScore calculateAverageScore = new CalculateAverageScore();

        removeHighestScore.setSuccessor(removeLowestScore);
        removeLowestScore.setSuccessor(calculateAverageScore);

        GymnasticGame game = new GymnasticGame();
        game.setHandler(removeHighestScore);
        game.handleRequest(score1);
        game.handleRequest(score2);
        game.handleRequest(score3);
    }
}