How to detect 'enter' when reading integers using Integer.parseInt

How could I detect the 'enter' and break (if number???) in the code below?

Thanks!

public static void readNumbers(Scanner reader, ArrayList<Integer> list) {

    System.out.println("Give numbers, ‘enter’ will stop.");

    while (true) {
        int number = Integer.parseInt(reader.nextLine());
        if (number ????) {
            break;
        }
        list.add(number);
    } 
 }