code: protected static void timestampFormat(String pattern, String... attributeNames) {
          ModelDelegate.timestampFormat(modelClass(), pattern, attributeNames);
      }
docs: Registers date format for specified attributes. This format will be used to convert between
  Date -> String -> java.sql.Timestamp when using the appropriate getters and setters.
  
  <p>For example:
  <blockquote><pre>
  public class Person extends Model {
  static {
  timestampFormat("MM/dd/yyyy hh:mm a", "birth_datetime");
  }
  }
  
  Person p = new Person();
  // will convert String -> java.sql.Timestamp
  p.setTimestamp("birth_datetime", "02/29/2000 12:07 PM");
  // will convert Date -> String, if dob value in model is of type Date or java.sql.Timestamp
  String str = p.getString("birth_datetime");
  
  // will convert Date -> String
  p.setString("birth_datetime", new Date());
  // will convert String -> java.sql.Timestamp, if dob value in model is of type String
  Timestamp ts = p.getTimestamp("birth_datetime");
  </pre></blockquote>
  
  @param pattern pattern to use for conversion
  @param attributeNames attribute names