Simple Strict Date Parsing

Saturday 2010-03-06

In Java, the DateFormat.parse() method is a funny little critter. It helps you by trying to figure out what date you actually meant when you typed in “35/12/2O10” (note the letter “O” in 2O10). In this case, it will parse the date without errors or warnings, and returns the date “11/12/04” (November 12th, 0004). That’s because it thinks “35” is a month, and “2” is the year, ignoring everything after the letter “O”.

DateFormat tries to convert the “35th month” into 2 years and 11 months, and correct the date accordingly. df.setLenient(false) prevents this, but that still leaves the problem of the parsing stopping at the first wrong character without warning.

I needed a much stricter way of parsing dates, and yesterday I found an elegant solution to this problem. It’s so small I was able to tweet it in less than 140 characters, but I thought it deserved a decent blogpost so here it goes:

public Date parseDateString(String inputDateString) 
         throws ParseException {
  DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT);
  Date parsedDate = df.parse(inputDateString);

  if (!inputDateString.equals(df.format(parsedDate))) {
    throw new ParseException("Invalid Date", 0);
  return parsedDate;

The brilliance here is in the comparing of the formatted date with the original input. The method returns a normal ParseException so you can perfectly replace your original df.parse() calls with it, making them more strict.

Thanks to Bas for this elegant and simple solution.


Ibatis Inline Parameter Maps

Tuesday 2010-02-16

Today I (re)discovered a feature in the Ibatis data mapper framework which was clearly documented, but for some reason was not being used in our project. The feature is called “inline parameter maps” and combined with a wrapper bean it can clean up a lot of clutter in the code and in the SqlMaps. Please feel free to share this example with your fellow Ibatis Data Mapper 2 framework users.

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Sonar “Close Connection” warning workaround.

Tuesday 2009-10-06

When you use Spring and Ibatis and SQLTemplates, you could have code in your project which looks somewhat like this:

Connection connection = DataSourceUtils.getConnection(getDataSource());
...<do connection stuff here>...
DataSourceUtils.releaseConnection(connection, getDataSource());

Sonar will report that you did not close the connection, while in fact, Spring did that for you. You can not just add a “connection.close()” to the code because the whole point of calling “releaseConnection()” is to have Spring handle all the smart stuff on committing, closing, and returning the connection to the pool if needed.

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Eclipse 3.4.1, OSX and Java 1.6

Sunday 2008-12-28

Eclipse application icon

I recently downloaded Eclipse 3.4.1 for Mac OSX, and tried starting it using the icon. It did not work, and I noticed a message in /var/log/system.log telling me that the JVM could not be loaded.

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J-Fall 2008

Thursday 2008-11-13

NLJUG small dukeLast wednesday I was at J-Fall 2008, a fairly large event for Java programmers in the Netherlands. This event is organized by NLJUG. You can read some of my notes on the different sessions in my public evernote.

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Spring SystemPropertyInitializingBean

Wednesday 2008-07-23

When using POI in any of your projects, and the application you’re building is a web application, you probably have it running on a Windows machine. If not, you know all about the struggle with the “headless mode” environment setting to tell the JVM how to handle graphics rendering.

I always like to keep my applications as clean as possible to the users. The system administrator is also a user of the software (during installation at least). So I wanted the application to set the environment properties itself, In this case, I built a nice little Spring bean to handle this. The solution is so simple, that it is almost a brilliant display of what Spring can solve for you. Suddenly, all these environment setting problems turned into a simple Spring configuration problem. Here’s how:

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Ibatis 2.2 Ignores XML encoding

Sunday 2008-07-20

At my company, we’re using Ibatis to do operations on Oracle databases. As most of our software is designed to be international, we keep our XML files in UTF-8 encoding. Recently we discovered that Ibatis had some trouble parsing the XML files when we were using diacritics in them. As it turns out, Ibatis 2.2 actually ignores the “UTF-8” setting in the XML file header altogether.

This was actually reported as an issue at apache’s issue tracker, and fixed in Ibatis release 2.3 and upward. In the meantime, if you can not swich to a new release because of tight deadlines and no time for regression tests, you can set the file.encoding property to UTF-8, because then Ibatis will parse the XML in the correct encoding.