Java Data Type - 如何比较两个枚举数据类型变量

enum Week {
  Monday, Tuesday, Wednesday, Thursday, Friday, Saturaday, Sunday
}

public class MainClass {
  public static void main(String args[]) {

    Week day1, day2, day3;
    day1 = Week.Monday;
    day2 = Week.Tuesday;
    day3 = Week.Friday;

    // 
    if (day1.compareTo(day2) < 0)
      System.out.println(day1 + " comes before " + day2);

    if (day2.compareTo(day3) > 0)
      System.out.println(day2 + " comes before " + day3);

    if (day1.compareTo(day3) == 0)
      System.out.println(day1 + " equals " + day3);

  }
}