Main.java

public class Main {

    public static void main(String[] args) {

        PrinterController.connectToPrinterA().commandA1();
        PrinterController.connectToPrinterB().commandB1();
        PrinterController.connectToPrinterC().commandC1();
    }
}

PrinterA.java

public class PrinterA {

    private static PrinterA instance;

    private PrinterA() {
    }

    public static PrinterA getInstance(){
        if(instance == null){
            return new PrinterA();
        }
        return instance;
    }

    public void commandA1(){
        // TODO: implement me
    }

    public void commandA2(){
        // TODO: implement me
    }
}

PrinterB.java

public class PrinterB {

    private static PrinterB instance;

    private PrinterB() {
    }

    public static PrinterB getInstance(){
        if(instance == null){
            return new PrinterB();
        }
        return instance;
    }

    public void commandB1(){
        // // TODO: implement me
    }

    public void commandB2(){
        // // TODO: implement me
    }
}

PrinterC.java

public class PrinterC {

    private static PrinterC instance;

    private PrinterC() {
    }

    public static PrinterC getInstance(){
        if(instance == null){
            return new PrinterC();
        }
        return instance;
    }

    public void commandC1(){
        // TODO: implement me
    }

    public void commandC2(){
        // TODO: implement me
    }
}

PrinterController.java

public class PrinterController {

    private PrinterController() {
    }

    public static PrinterA connectToPrinterA(){
        return PrinterA.getInstance();
    }

    public static PrinterB connectToPrinterB(){
        return PrinterB.getInstance();
    }

    public static PrinterC connectToPrinterC(){
        return PrinterC.getInstance();
    }
}