/** This class demonstrates race condition.
    It needs the Depositer and Withdrawer classes.
 */
public class Account {
  private int balance;
  private boolean depositFlag;
  private boolean withdrawFlag;

  public Account(int startBalance) {
    balance = startBalance;
    stopDeposit();
    stopWithdraw();
  }

  public void startDeposit() {
    depositFlag = true;
  }

  public void startWithdraw() {
    withdrawFlag = true;
  }

  public boolean isDepositing() {
    return depositFlag;
  }

  public boolean isWithdrawing() {
    return withdrawFlag;
  }

  public void stopDeposit() {
    depositFlag = false;
  }

  public void stopWithdraw() {
    withdrawFlag = false;
  }

  public /* synchronized */ void deposit(int amount) {
    /*    balance += amount; */
    int b = balance;
    try {
      Thread.sleep((int) (Math.random()*10));
      balance = b + amount;
    } catch (Exception e) {};
  }

  public /* synchronized */ void withdraw(int amount) {
    /*    balance -= amount; */
    int b = balance;
    try {
      Thread.sleep((int) (Math.random()*10));
      balance = b - amount;
    } catch (Exception e) {};
  }

  public void showBalance() {
    System.out.print("$" + balance);
  }

  public static void main(String[] args) {
    Account ac = new Account(10000);

    System.out.print("Begining balance: ");
    ac.showBalance();
    System.out.println();

    Depositer d = new Depositer(ac);
    Withdrawer w = new Withdrawer(ac);
    d.start();
    w.start();

    while (ac.isDepositing() || ac.isWithdrawing()) {
      try {
        Thread.sleep(10);
      } catch (Exception e) {};
    }

    System.out.print("Ending balance: ");
    ac.showBalance();
    System.out.println();
  }
}