class DirectedAcyclicGraph extends SimpleDirectedGraph<V, E> implements Iterable<V> {

    public Iterator<V> iterator()
    {
        return new TopoIterator();
    }

    public  DirectedAcyclicGraph(Class<? extends E> edgeClass);
    public  DirectedAcyclicGraph(Class<? extends E> edgeClass, boolean weighted);
    public  DirectedAcyclicGraph(EdgeFactory<V, E> ef);
    public  DirectedAcyclicGraph(EdgeFactory<V, E> ef, boolean weighted);
    protected  DirectedAcyclicGraph(
        EdgeFactory<V, E> ef, VisitedStrategyFactory visitedStrategyFactory,
        TopoOrderMap<V> topoOrderMap, boolean weighted);

}