监视Java两台打印机

Question

我实现了两台打印机无法同时打印的两台打印机的问题，例如打印机A正在打印而B不能，就像它一样简单，我用Semaphores做了如下：

我的Printer.class看起来像

public class Printer extends Thread {

    Semaphore mutex,multiplex;
    PrinterMachine printerMachine;
    String printer = "";
    public Printer(Semaphore mutex, Semaphore multiplex, PrinterMachine pm) {
        this.multiplex = multiplex;
        this.mutex = mutex;
        printerMachine = pm;
    }
    @Override
    public void run() {
        String printer = "";
        for(;;) {
            try {multiplex.acquire();} catch (InterruptedException e) {}
            try {mutex.acquire();} catch (InterruptedException e) {}
            if(printerMachine.getCanPrintA()) {
                printer = "A";
                printerMachine.setCanPrintA(false); 
            }
            else {
                printer="B";
                printerMachine.setCanPrintB(false); 
            }
            mutex.release();
            try {Thread.sleep(100);} catch (InterruptedException e) {}
            System.out.println(printer);
            if(printer.equals("A")) {
                printerMachine.setCanPrintA(true);
                }
            else {
                printerMachine.setCanPrintB(true);
            }
            try {Thread.sleep(100);} catch (InterruptedException e) {}
            multiplex.release();
        }
    }

}

然后我有一个共享变量的类

class PrinterMachine{
    public volatile Boolean canPrintA = true,canPrintB = true;
.... //Getter and Setter

然后我有我的主要

public static void main(String[] args) {
        Semaphore mutex = /* COMPLETE */ new Semaphore(1);
        Semaphore multiplex = /* COMPLETE */ new Semaphore(2);
        PrinterMachine pm = new PrinterMachine();

        Printer printers[] = new Printer[10];
        for (int i = 0 ; i<printers.length; i++) {
            printers[i] = new Printer(mutex,multiplex,pm);
            printers[i].start();
        }   
        try {
            Thread.sleep(5000);
        }
        catch(InterruptedException ie) {}
        for (int i = 0 ; i<printers.length; i++) {
            printers[i].stop();
        }
    }

它工作正常，但我想知道如何更改我的信号量以使用monitors代替？

修改

问题？

我有两台打印机而且我无法同时打印文档（System.out.println（）），所以我用Semaphores做了一个程序来执行此操作，并且我无法在A和B上打印同时打印机，现在我尝试使用信号量而不是使用信号量。使用监视器。