Programmatically constructing sequences ("a", "b", "c") for XQuery

[Michael Ludwig]

I'm reposting a question that I already asked in a similar form on the
Berkeley DB XML forum [1].

Let's say I have a prepared query like this:

   collection('import')[//File = $files]

Now I would like to be $files a sequence of strings:

   ('eins','zwei','drei')

Does anyone know of a way to achieve this? It might be at the XQuery
level or at the Java (or whatever) level.

In Java, would you use java.lang.StringBuilder? And then append quotes
and commas? Or is there a better, safer way?

[1] http://forums.oracle.com/forums/thread.jspa?threadID=940849

-- 
Michael Ludwig