enum 用法

public enum WeekDay {
  SUN(, "Sunday", "SUN"),
  MON(, "Monday", "MON"),
  TUE(, "Tuesday", "TUE"),
  WED(, "Wednesday", "WED"),
  THU(, "Thursday", "THU"),
  FRI(, "Friday", "FRI"),
  SAT(, "Saturday", "SAT");
 
  private String shortName;
  private String fullName;
  private int dayOfWeek;
  private WeekDay(int dayOfWeek, String name, String sname) {
    this.dayOfWeek = dayOfWeek;
    fullName = name;
    shortName = sname;
  }
 
  public static WeekDay getDay(int dayIndex)
  {
    switch (dayIndex) {
    case : return SUN;
    case : return MON;
    case : return TUE;
    case : return WED;
    case : return THU;
    case : return FRI;
    case : return SAT;
    }
    return null;
  }
 
  public String getShortName() {
    return shortName;
  }
 
  public int getDayOfWeek() {
    return dayOfWeek;
  }
 
  @Override
  public String toString() {
    return fullName;
  }
}