Modern language for ad-hoc XML queries?

[ANeoN]

I have to do some data mining on XML documents lately. Most of it ad-hoc, i.e, I don't have the schema of the documents in advance, and I only run the query a couple of times. Some example queries are "how many elements have this sub-element value greater than 0" or "per some kind of elements, what is the sum of the values of some of their sub-elements".Running such queries in Java is awkward because (a) Java DOM processing is really cumbersome, and (b) I only need to run these queries a for a few times, not as a part of an application.What is a recommended and currently-supported query language and tool for this scenario? Preferably interactive, free/open-source, and does not require storing the document in a database in advance (although it's an option).