Multithread construction algorithm of immutable tree in Java

I want to build an immutable tree data structure that represents any subset of the filsystem directory structure There is usually a filter that knows include / exclude. I basically want some thread support in the construction

It sounds like writing your own pure nerd fun, but I actually wonder if there are any good examples, texts or similar on this topic? The source code is very good;)

Solution

This book has all the answers: http://www.amazon.co.uk/Purely-Functional-Structures-Chris-Okasaki/dp/0521663504