How many problems are in the following date parsing routines that come from a real-world project?

Question

These methods are laughably stupid, IMO, but I want to get a feel for what other developers think of such code. Criticisms may include technical and stylistic errors. Corrections may use anything from Apache commons-lang, such as StringUtils, DateUtils, etc, as well as anything in Java 5. The code is intended for a web application, if that would affect your style. These four methods are all defined in the same file, too, if that matters. Did I mention that there are no unit tests for this code either?! What would you do to fix the situation? I just happened upon this file, and it's not my immediate task to fix this code. I could in my spare time, if so desired.

Method one:

   public static boolean isFromDateBeforeOrSameAsToDate(final String fromDate,
     final String toDate) {
 boolean isFromDateBeforeOrSameAsToDate = false;
 Date fromDt = null;
 Date toDt = null;
 try {
     fromDt = CoreUtils.parseTime(fromDate, CoreConstants.DATE_PARSER);
     toDt = CoreUtils.parseTime(toDate, CoreConstants.DATE_PARSER);
     // if the FROM date is same as the TO date - its OK
     // if the FROM date is before the TO date - its OK
     if (fromDt.before(toDt) || fromDt.equals(toDt)) {
  isFromDateBeforeOrSameAsToDate = true;

     }
 } catch (ParseException e) {
     e.printStackTrace();
 }
 return isFromDateBeforeOrSameAsToDate;
    }

Method two:

    public static boolean isDateSameAsToday(final Date date) {
 boolean isSameAsToday = false;

 if (date != null) {
     Calendar current = Calendar.getInstance();
     Calendar compare = Calendar.getInstance();
     compare.setTime(date);

     if ((current.get(Calendar.DATE) == compare.get(Calendar.DATE))
      && (current.get(Calendar.MONTH) == compare
       .get(Calendar.MONTH))
      && (current.get(Calendar.YEAR) == compare
       .get(Calendar.YEAR))) {
  isSameAsToday = true;
     }

 }
 return isSameAsToday;
    }

Method three:

    public static boolean areDatesSame(final String fromDate,
     final String toDate) {
 boolean areDatesSame = false;
 Date fromDt = null;
 Date toDt = null;
 try {
     if (fromDate.length() > 0) {
  fromDt = CoreUtils.parseTime(fromDate,
   CoreConstants.DATE_PARSER);
     }
     if (toDate.length() > 0) {
  toDt = CoreUtils.parseTime(toDate, CoreConstants.DATE_PARSER);
     }
     if (fromDt != null && toDt != null) {
  if (fromDt.equals(toDt)) {
      areDatesSame = true;
  }
     }

 } catch (ParseException e) {
     if (logger.isDebugEnabled()) {
  e.printStackTrace();
     }
 }
 return areDatesSame;
    }

Method four:

    public static boolean isDateCurrentOrInThePast(final Date compareDate) {
 boolean isDateCurrentOrInThePast = false;
 if (compareDate != null) {
     Calendar current = Calendar.getInstance();
     Calendar compare = Calendar.getInstance();
     compare.setTime(compareDate);

     if (current.get(Calendar.YEAR) > compare.get(Calendar.YEAR)) {
  isDateCurrentOrInThePast = true;
     }

     if (current.get(Calendar.YEAR) == compare.get(Calendar.YEAR)) {
  if (current.get(Calendar.MONTH) > compare.get(Calendar.MONTH)) {
      isDateCurrentOrInThePast = true;
  }

     }

     if (current.get(Calendar.YEAR) == compare.get(Calendar.YEAR)) {
  if (current.get(Calendar.MONTH) == compare.get(Calendar.MONTH)) {
      if (current.get(Calendar.DATE) >= compare
       .get(Calendar.DATE)) {
   isDateCurrentOrInThePast = true;
      }

  }

     }

 }
 return isDateCurrentOrInThePast;
    }

Here is how I would tend to write the same thing (well, first I would write unit tests, but I'll skip that here).

    public static int compareDatesByField(final Date firstDate,
     final Date secondDate, final int field) {

 return DateUtils.truncate(firstDate, field).compareTo(
  DateUtils.truncate(secondDate, field));
    }

    public static int compareDatesByDate(final Date firstDate,
     final Date secondDate) {
 return compareDatesByField(firstDate, secondDate, Calendar.DATE);
    }

// etc. as required, although I prefer not bloating classes which little
// methods that add little value ...

// e.g., the following methods are of dubious value, depending on taste
    public static boolean lessThan(int compareToResult) {
 return compareToResut < 0;
    }
    public static boolean equalTo(int compareToResult) {
 return compareToResut == 0;
    }
    public static boolean greaterThan(int compareToResult) {
 return compareToResut > 0;
    }
    public static boolean lessThanOrEqualTo(int compareToResult) {
 return compareToResut <= 0;
    }
    public static boolean greaterThanOrEqualTo(int compareToResult) {
 return compareToResut >= 0;
    }

// time-semantic versions of the dubious methods - perhaps these go in TimeUtils ?


   public static boolean before(int compareToResult) {
 return compareToResut < 0;
    }
    public static boolean on(int compareToResult) {
 return compareToResut == 0;
    }
    public static boolean after(int compareToResult) {
 return compareToResut > 0;
    }
    public static boolean onOrBefore(int compareToResult) {
 return compareToResut <= 0;
    }
    public static boolean onOrAfter(int compareToResult) {
 return compareToResut >= 0;
    }

Clients could then use the method as follows:

/* note: Validate library from Apache Commons-Lang throws 
 * IllegalArgumentException when arguments are not valid 
 * (this comment would not accompany actual code since the
 * Javadoc for Validate would explain that for those unfamiliar with it)
 */
 Validate.isTrue(onOrAfter(compareDatesByDate(registrationDate, desiredEventDate),
     "desiredEventDate must be on or after the *day* of registration: ", desiredEventDate);

Answer 1

First thing, fix the indentation. Ctrl+Shift+F in Eclipse.

I can't stand incorrectly indented code.

Next, write unit tests for all the methods you touch, before you touch them.

Also, use JodaTime. It beats the standard Java date classes to a bloody pulp. A lot of the ugly date logic will be taken care of by switching to it.

Answer 2

There are all sort of issues here. For instance: why static method? But my #1 problem is Lack of unit tests. Whatever refactoring we'd like to apply here, we need tests to make sure we didn't break anything.

Thus, I will start with writing unit tests. All other issues are secondary to that.