[Java]LeetCode1195. Fizz Buzz多线程 | Fizz Buzz Multithreaded

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Write a program that outputs the string representation of numbers from 1 to n, however:

• If the number is divisible by 3, output "fizz".
• If the number is divisible by 5, output "buzz".
• If the number is divisible by both 3 and 5, output "fizzbuzz".

For example, for n = 15, we output: 1, 2, fizz, 4, buzz, fizz, 7, 8, fizz, buzz, 11, fizz, 13, 14, fizzbuzz.

Suppose you are given the following code:

class FizzBuzz {
  public FizzBuzz(int n) { ... }               // constructor
  public void fizz(printFizz) { ... }          // only output "fizz"
  public void buzz(printBuzz) { ... }          // only output "buzz"
  public void fizzbuzz(printFizzBuzz) { ... }  // only output "fizzbuzz"
  public void number(printNumber) { ... }      // only output the numbers
}

Implement a multithreaded version of FizzBuzz with four threads. The same instance of FizzBuzz will be passed to four different threads:

1. Thread A will call fizz() to check for divisibility of 3 and outputs fizz.
2. Thread B will call buzz() to check for divisibility of 5 and outputs buzz.
3. Thread C will call fizzbuzz() to check for divisibility of 3 and 5 and outputs fizzbuzz.
4. Thread D will call number() which should only output the numbers.

---

class FizzBuzz {
    
    private int n;
    private int currentNumber = 1;
    
    public FizzBuzz(int n) {
        this.n = n;
    }

    // printFizz.run() outputs "fizz".
    public synchronized void fizz(Runnable printFizz) throws InterruptedException {
        while (currentNumber <= n) {
            if (currentNumber % 3 != 0 || currentNumber % 5 == 0) {
                wait();
                continue;
            }
            printFizz.run();
            currentNumber += 1;
            notifyAll();
        }
    }

    // printBuzz.run() outputs "buzz".
    public synchronized void buzz(Runnable printBuzz) throws InterruptedException {
        while (currentNumber <= n) {
            if (currentNumber % 5 != 0 || currentNumber % 3 == 0) {
                wait();
                continue;
            }
            printBuzz.run();
            currentNumber += 1;
            notifyAll();
        }
    }

    // printFizzBuzz.run() outputs "fizzbuzz".
    public synchronized void fizzbuzz(Runnable printFizzBuzz) throws InterruptedException {
        while (currentNumber <= n) {
            if (currentNumber % 15 != 0) {
                wait();
                continue;
            }
            printFizzBuzz.run();
            currentNumber += 1;
            notifyAll();
        }
    }

    // printNumber.accept(x) outputs "x", where x is an integer.
    public synchronized void number(IntConsumer printNumber) throws InterruptedException {
        while (currentNumber <= n) {
            if (currentNumber % 3 == 0 || currentNumber % 5 == 0) {
                wait();
                continue;
            }
            printNumber.accept(currentNumber);
            currentNumber += 1;
            notifyAll();
        }
    }
}