ArrayList roots = new ArrayList();
ArrayList<ModuleNode> roots = new ArrayList<ModuleNode>();
    public ArrayList findInputs() {        ArrayList roots = new ArrayList();        Collection nodes = getNodes(null);        Iterator i = nodes.iterator();        while (i.hasNext()) {            ModuleNode node = (ModuleNode) i.next();            if (node.getSourceCount() == 0) {                roots.add(node);            }        }        return roots;    }