Java - generate class diagram by myself

I am working on a small project in Java described below:

Input: List of objects for directed graph. ( Nodes with different kind of edges: inheritance, inner-class, friend classes, etc. ) Output: class diagram, as planar as possible.

My problem is: I would like to have some 3rd party software that will do it for me or at least have an algorithm of selecting nodes and edges to keep my graph as planar as possible.

EDIT: I see I may not have written clearly what I want... I don't want to generate class diagram based on Java project with its files, but I am parsing C++ file and get from there list described in above input. Then I want to call some function on that开发者_如何学C list and get my diagram. I was trying to use JGraph or JGraphT but I unfortunately didn't find any graph-theory functionality which suit my requirements.

Regards, Daniel

If you use Eclipse IDE you can use Soyatec's eUML2 free plugin. Have a look here.