Recalculate Links through Autolayout Man

I am using JGo auto layout package. There are situations where I want to perform auto-layout only on links like giving the user the option to recalculate the links in diagram. I played a little with the functionality JGoLayeredDigraphAutoLayout provaides. I found a method called layoutLinks(). I initialized the auto-layout manager with my document and called that method. The operation failed on NullPointerException.
I need that functionality.
Waht did I do wrong?

It’s depending on the JGoNetwork being set up correctly, as would normally happen when you call performLayout().
I haven’t tried this, but maybe you could just override layoutNodes() to be a no-op, and then just call performLayout() normally.
To speed things up, you could override reduceCrossings() and straightenAndPack() to be no-ops too, since you’re not trying to arrange the nodes.