public Collection<Tree<V, E>> getTrees() {
			return ((Forest<V,E>)delegate).getTrees();
		}

        public int getChildCount(V vertex)
        {
            return ((Forest<V,E>)delegate).getChildCount(vertex);
        }

        public Collection<E> getChildEdges(V vertex)
        {
            return ((Forest<V,E>)delegate).getChildEdges(vertex);
        }

        public Collection<V> getChildren(V vertex)
        {
            return ((Forest<V,E>)delegate).getChildren(vertex);
        }

        public V getParent(V vertex)
        {
            return ((Forest<V,E>)delegate).getParent(vertex);
        }

        public E getParentEdge(V vertex)
        {
            return ((Forest<V,E>)delegate).getParentEdge(vertex);
        }
	}
	
	@SuppressWarnings("serial")
    static class UnmodifiableTree<V,E> extends UnmodifiableForest<V,E>

    	edge_index.put(e, count);
    	return count;
     }
    
    protected int getIndex(Graph<V,E> graph, E e, V v) {
    	Collection<E> commonEdgeSet = new HashSet<E>();
    	for(E another : graph.getIncidentEdges(v)) {
    		V u = graph.getOpposite(v, another);
    		if(u.equals(v)) {
    			commonEdgeSet.add(another);
    		}
    	}
    	int count=0;
    	for(E other : commonEdgeSet) {
    		if(e.equals(other) == false) {
    			edge_index.put(other, count);

			throw new UnsupportedOperationException();
		}

		/**
		 * @see edu.uci.ics.jung.graph.Hypergraph#isIncident(java.lang.Object, java.lang.Object)
		 */
		public boolean isIncident(V vertex, E edge) {
			return delegate.isIncident(vertex, edge);
		}

		/**
		 * @see edu.uci.ics.jung.graph.Hypergraph#isNeighbor(java.lang.Object, java.lang.Object)
		 */
		public boolean isNeighbor(V v1, V v2) {
			return delegate.isNeighbor(v1, v2);
		}

		/**
		 * @see edu.uci.ics.jung.graph.Hypergraph#degree(java.lang.Object)
		 */
		public int degree(V vertex) {
			return delegate.degree(vertex);
		}

		/**
		 * @see edu.uci.ics.jung.graph.Hypergraph#findEdge(java.lang.Object, java.lang.Object)
		 */
		public E findEdge(V v1, V v2) {
			return delegate.findEdge(v1, v2);
		}
        
        /**
         * @see edu.uci.ics.jung.graph.Hypergraph#findEdgeSet(java.lang.Object, java.lang.Object)
         */
        public Collection<E> findEdgeSet(V v1, V v2)
        {
            return delegate.findEdgeSet(v1, v2);
        }

		/**
		 * @see edu.uci.ics.jung.graph.Hypergraph#getEdges()
		 */
		public Collection<E> getEdges() {