Sorting Derived (Transient) Domain Properties in Grails

Every time someone on the Grails list or StackOverflow remarks that sorting only works in GORM with database persisted properties, I'm left scratching my head why post database faulting results can't be easily sorted. Groovy actually enables this with its own List.sort() mechanism, which I've not posted an example of in the Derived Sorts project on github.

The key to the sorting is to know what fields can be sorted without custom code, and then based on a stringent selection of sortable properties, one can post-sort the results, including secondary sorts. It gets rather complicated quickly when you consider multiple sort criteria. Here's a direct link to the controller code. Any hints to clean it up further for future readers all welcome. The code now shows working pagination. I used the solution for PaginatebleList that Colin Harrington posted.