question: public static < E extends Enum < E > & BitmapableEnum > EnumSet < E > toEnumSet ( Class < E > type , int bitmap ) { if ( type == null ) throw new NullPointerException ( "Given enum type must not be null" ) ; EnumSet < E > s = EnumSet . noneOf ( type ) ; int allSetBitmap = 0 ; for ( E element : type . getEnumConstants ( ) ) { if ( Integer . bitCount ( element . getValue ( ) ) != 1 ) { String msg = String . format ( "The %s (%x) constant of the " + "enum %s is supposed to represent a bitmap entry but " + "has more than one bit set." , element . toString ( ) , element . getValue ( ) , type . getName ( ) ) ; throw new IllegalArgumentException ( msg ) ; } allSetBitmap |= element . getValue ( ) ; if ( ( bitmap & element . getValue ( ) ) != 0 ) s . add ( element ) ; } if ( ( ( ~ allSetBitmap ) & bitmap ) != 0 ) { String msg = String . format ( "The bitmap %x for enum %s has " + "bits set that are presented by any enum constant" , bitmap , type . getName ( ) ) ; throw new IllegalArgumentException ( msg ) ; } return s ; }
target:  Convert an integer bitmap to an EnumSet. See class description for example