class MoneyCounter {

private int moneyAvailable = 2000;

public synchronized void useMoney(String userName, int numberOfMoney) {

if (numberOfMoney <= moneyAvailable) {

moneyAvailable -= numberOfMoney;

System.out.println(userName + " used " + numberOfMoney + " money. Money left: " + moneyAvailable);

}

}

public synchronized int getMoneyAvailable() {

return moneyAvailable;

}

}

class BuyBook implements Runnable {

private MoneyCounter moneyCounter;

private String userName;

private int price;

public BuyBook(MoneyCounter moneyCounter, String userName, int price) {

this.moneyCounter = moneyCounter;

this.userName = userName;

this.price = price;

}

@Override

public void run() {

while(true) {

moneyCounter.useMoney(userName, price);

}

}

}

class BuyFood implements Runnable {

private MoneyCounter moneyCounter;

private String userName;

private int price;

public BuyFood(MoneyCounter moneyCounter, String userName, int price) {

this.moneyCounter = moneyCounter;

this.userName = userName;

this.price = price;

}

@Override

public void run() {

while(true) {

moneyCounter.useMoney(userName, price);

}

}

}

class BuyTicket implements Runnable {

private MoneyCounter moneyCounter;

private String userName;

private int price;

public BuyTicket(MoneyCounter moneyCounter, String userName, int price) {

this.moneyCounter = moneyCounter;

this.userName = userName;

this.price = price;

}

@Override

public void run() {

while(true) {

moneyCounter.useMoney(userName, price);

}

}

}

public class UseMoneyTest {

public static void main(String[] args) {

MoneyCounter moneyCounter = new MoneyCounter();

Thread thread1 = new Thread(new BuyBook(moneyCounter, "User1", 5));

Thread thread2 = new Thread(new BuyFood(moneyCounter, "User2", 10));

Thread thread3 = new Thread(new BuyTicket(moneyCounter, "User3", 20));

thread1.start();

thread2.start();

thread3.start();

}

}