Dear Kettle fans,

Daniel & I had a lot of fun in Orlando last week. Among other things we worked on the User Defined Java Class (UDJC) step.  If you have a bit of Java Experience, this step allows you to quickly write your own plugin in a step. This step is available in recent builds of Pentaho Data Integration (Kettle) version 4.

Now, how does this work?  Well, let’s take Roland Bouman’s example : the calculation of the the date of Easter.  In this blog post, Roland explains how to calculate Easter in MySQL and Kettle using JavaScript.  OK, so what if you want this calculation to be really fast in Kettle?  Well, then you can turn to pure Java to do the job…

To whom it may concern,
A MySQL stored function to calculate easter day
I uploaded a MySQL forge snippet for the f_easter() function. You can use this function in MySQL statements to calculate easter sunday for any given year:

mysql>  select f_easter(year(now()));
+-----------------------+
| f_easter(year(now())) |
+-----------------------+
| 2010-04-04            |
+-----------------------+
1 row in set (0.00 sec)

Anonymous Gregorian algorithm
To implement it, I simply transcribed the code of the "Anonymous Gregorian algorithm" from wikipedia's Computus article.

You might ask yourself: "how does …