Tree (directed acyclic graph) implementation

Question

I require a tree / directed acyclic graph implementation something like this:

public class TreeNode {
    private K key; // \'key\' for this node         


        

Answer 1

There's also http://www.jgrapht.org, which has software licensed under the LGPL. I have to warn you though, implementing your own is fraught with danger. If you plan on using recursion on your structure (which is a graph), you'll have to ensure that it's acyclic, or you'll run into infinite loop problems. Better to use third party code where they've already dealt with the issues.