What prevents you from using solely Cache API and why do you need TreeCache API?
My cached data is a strictly hierarchical data structure.
Have you thought about using JCR API? Beside of trees you have there different query languages to select data. Have a look at Modeshape. Modeshape can btw. use Infinspan as storage engine...
Thank you very much for taking the time to provide such good answers to my questions.
Modeshape looks pretty good so far ... I had never heard of it before.