java - 为多线程 FizzBu​​zz 编写测试用例

Question

我正在通过此链接解决 LeetCode 问题:https://leetcode.com/problems/fizz-buzz-multithreaded/ .
基本上，我正在编写一个执行标准 fizzbuzz 的 FizzBu​​zz 类，但同时运行 4 个线程，每个线程调用不同的方法。 (一个线程正在调用 fizzbuzz，一个线程在调用 fizz，一个调用 buzz 和一个调用号码)。这是我接受的解决方案:

class FizzBuzz {
     private int n;
     int num = 1; // FizzBuzz starts at 1.
     public FizzBuzz(int n) {
         this.n = n;
     }

     // printFizz.run() outputs "fizz".
     public synchronized void fizz(Runnable printFizz) throws InterruptedException {
         while(num <= n) {
             if(num % 3 == 0 && num % 5 != 0) {
                 printFizz.run();
                 num++;
                 notifyAll();
             } else {
                 wait();
             }
         }
     }

     // printBuzz.run() outputs "buzz".
     public synchronized void buzz(Runnable printBuzz) throws InterruptedException {
         while(num <= n) {
             if(num % 3 != 0 && num % 5 == 0) {
                 printBuzz.run();
                 num++;
                 notifyAll();
             } else {
                 wait();
             }
         }
     }

     // printFizzBuzz.run() outputs "fizzbuzz".
     public synchronized void fizzbuzz(Runnable printFizzBuzz) throws InterruptedException {
         while(num <= n) {
             if(num % 15 == 0) {
                 printFizzBuzz.run();
                 num++;
                 notifyAll();
             } else {
                 wait();
             }
         }
     }



     // printNumber.accept(x) outputs "x", where x is an integer.
     public synchronized void number(IntConsumer printNumber) throws InterruptedException {
         while(num <= n) {
             if(num % 3 != 0 && num % 5 != 0) {
                 printNumber.accept(num);
                 num++;
                 notifyAll();
             } else {
                 wait();
             }
         }
     }
} 

问题是我很难在我的 IDE 中模拟这种情况。
这是我的主要方法:

    public class FizzBuzzMain {
        public static void main(String[] args) {
            FizzBuzz fizzBuzz = new FizzBuzz(15);
            Runnable printFizzBuzz = new PrintFizzBuzz();
            Runnable printFizz = new PrintFizz();
            Runnable printBuzz = new PrintBuzz();
            
            Thread t1 = new Thread(printFizzBuzz);
            Thread t2 = new Thread(printFizz);
            Thread t3 = new Thread(printBuzz);
            IntConsumer printNumber = new PrintNumber();
            
            t1.start();
            t2.start();
            t3.start();
            
            try {
                fizzBuzz.number(printNumber);
                fizzBuzz.fizz(printFizz);
                fizzBuzz.buzz(printBuzz);
                fizzBuzz.buzz(printFizzBuzz);
            } catch(Exception e) {
                e.printStackTrace();
            }
        }
    } 
 

我想用 IntConsumer 初始化第四个线程(这是从问题中给出的)，这样我也可以执行 t4 ，但我不知道该怎么做。显然，我的 main 方法在某个时刻停止运行，因为所有线程都进入等待状态并且没有人唤醒它们(此处缺少 t4)。
任何帮助将不胜感激!

Answer 1

我修复了您的类，以便您可以在 IDE 中运行它，然后实现了 Emma 提供的解决方案:

abstract class FizzBuzzRunner implements Runnable {

    protected FizzBuzz fizzBuzz;

    public FizzBuzzRunner(FizzBuzz fizzBuzz) {
        this.fizzBuzz = fizzBuzz;
    }

    abstract protected void print();
}

class PrintFizz extends FizzBuzzRunner {

    public PrintFizz(FizzBuzz fizzBuzz) {
        super(fizzBuzz);
    }

    @Override
    public void run() {
        try {
            this.fizzBuzz.fizz(this);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    @Override
    protected void print() {
        System.out.println("fizz");
    }
}

class PrintBuzz extends FizzBuzzRunner {

    public PrintBuzz(FizzBuzz fizzBuzz) {
        super(fizzBuzz);
    }

    @Override
    public void run() {
        try {
            this.fizzBuzz.buzz(this);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    @Override
    protected void print() {
        System.out.println("buzz");
    }
}

class PrintFizzBuzz extends FizzBuzzRunner {

    public PrintFizzBuzz(FizzBuzz fizzBuzz) {
        super(fizzBuzz);
    }

    @Override
    public void run() {
        try {
            this.fizzBuzz.fizzbuzz(this);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    @Override
    protected void print() {
        System.out.println("fizzbuzz");
    }
}

class IntConsumer extends PrintFizzBuzz {

    public IntConsumer(FizzBuzz fizzBuzz) {
        super(fizzBuzz);
    }

    @Override
    public void run() {
        try {
            this.fizzBuzz.number(this);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public void accept(int n) {
        System.out.println(n);
    }
}

对主要的一个小改动:

public class Main {
public static void main(String[] args) {
    FizzBuzz fizzBuzz = new FizzBuzz(15);
    Runnable printFizzBuzz = new PrintFizzBuzz(fizzBuzz);
    Runnable printFizz = new PrintFizz(fizzBuzz);
    Runnable printBuzz = new PrintBuzz(fizzBuzz);
    Runnable printNumber = new IntConsumer(fizzBuzz);

    Thread t1 = new Thread(printFizzBuzz);
    Thread t2 = new Thread(printFizz);
    Thread t3 = new Thread(printBuzz);
    Thread t4 = new Thread(printNumber);

    t1.start();
    t2.start();
    t3.start();
    t4.start();
}
}

最后是 FizzBu​​zz 类:

class FizzBuzz {
private int n;
private Semaphore semNumber;
private Semaphore semFizz;
private Semaphore semBuzz;
private Semaphore semFizzBuzz;

public FizzBuzz(int n) {
    this.n = n;
    semNumber = new Semaphore(1);
    semFizz = new Semaphore(0);
    semBuzz = new Semaphore(0);
    semFizzBuzz = new Semaphore(0);
}

// printFizz.print() outputs "fizz".
public void fizz(FizzBuzzRunner printFizz) throws InterruptedException {
    for (int counter = 3; counter <= n; counter += 3) {
        semFizz.acquire();
        printFizz.print();

        if ((counter + 3) % 5 == 0) {
            counter += 3;
        }

        semNumber.release();
    }
}

// printBuzz.print() outputs "buzz".
public void buzz(FizzBuzzRunner printBuzz) throws InterruptedException {
    for (int counter = 5; counter <= n; counter += 5) {
        semBuzz.acquire();
        printBuzz.print();

        if ((counter + 5) % 3 == 0) {
            counter += 5;
        }

        semNumber.release();
    }
}

// printFizzBuzz.print() outputs "fizzbuzz".
public void fizzbuzz(FizzBuzzRunner printFizzBuzz) throws InterruptedException {
    for (int counter = 15; counter <= n; counter += 15) {
        semFizzBuzz.acquire();
        printFizzBuzz.print();
        semNumber.release();
    }
}

// printNumber.accept(x) outputs "x", where x is an integer.
public void number(IntConsumer printNumber) throws InterruptedException {
    for (int counter = 1; counter <= n; counter++) {
        semNumber.acquire();

        if (counter % 15 == 0) {
            semFizzBuzz.release();

        } else if (counter % 5 == 0) {
            semBuzz.release();

        } else if (counter % 3 == 0) {
            semFizz.release();

        } else {
            printNumber.accept(counter);
            semNumber.release();
        }
    }
}
}