Time to be more Groovy

Following a recommendation from a colleague, I've had good intentions to learn and use more Groovy for quite a while now, but somehow havent quite had a problem that really presents itself as the ideal starting point.

A few months back I took the initial plunge and used Groovy to do a real job. The job probably wasnt the best choice as a first Groovy project - it was basically pulling data from a multi-gigabyte binary file (actually WebLogic JMS storage files), but it needed to be done and I got the job done with Groovy. In the end I probably wished I hadn't done it this way because I couldn't then use the resulting script anywhere else without getting Groovy set up there first and the alternative was shifting the huge files to the machine where the script was working. I don't think I really learned much idiomatic Groovy either.

Today I have a new problem to solve - basically I have some complex pricing calculations to do based on data in a relational database. The calculations need to be done both in scheduled batch mode and 'on the fly' within a J2EE app for 'what-if' style illustrations. They also need to be very pluggable so that entirely different pricing structures can be supported.

Thinking about this problem, what I need is:-

• Must be runnable from a J2EE app
• Must have good DB integration
• Must have automated unit tests
• Must have concise, expressive logic and preferably polymorphism
• Must be easy to debug

The initial prototype (with lots of simplifying assumptions) was done as a stored procedure with DBUnit test cases, which nicely meets the first three requirements, but runs out of steam on the third. I think that continuing with this approach is going to result in something pretty cumbersome as I gradually remove the simplifying assumptions.

Native Java didn't seem too attractive in terms of really tight DB integration - both JDBC and Hibernate fall a long way short of the simplicity with which SQL can be used in a stored procedure.

So I took another look at Groovy - it seems to fit the bill pretty well. I suspect that GSQL will be rather less cumbersome than either raw JDBC or Hibernate, although probably not quite as closely integrated as running SQL inside a stored proc. I was also worried (based on past experience of Jython and Javascript) about debugging, but it seems that this angle is also covered with both JSwat and Eclipse being supported. Hopefully it will also get me into more idiomatic Groovy in the process...

We shall see!