template<class DG, class AT, class AP = Identity_policy_2<DG,AT> >
class Voronoi_diagram_2
{
 private:
  typedef Voronoi_diagram_2<DG,AT,AP>        Self;
  typedef Triangulation_cw_ccw_2             CW_CCW_2;

  friend struct CGAL_VORONOI_DIAGRAM_2_INS::Accessor<Self>;
 public:
  //-------
  // TYPES
  //-------

  // TYPES FOR THE DUAL GRAPH

  // the (triangulated) dual graph
  typedef DG                                          Delaunay_graph;
  typedef AT                                          Adaptation_traits;
  typedef AP                                          Adaptation_policy;

  typedef typename Delaunay_graph::Geom_traits        Delaunay_geom_traits;

  typedef typename Delaunay_graph::size_type          size_type;

  typedef typename Delaunay_graph::Vertex_handle      Delaunay_vertex_handle;
  typedef typename Delaunay_graph::Face_handle        Delaunay_face_handle;
  typedef typename Delaunay_graph::Edge               Delaunay_edge;

 protected:
  typedef typename Delaunay_graph::Edge_circulator    Dual_edge_circulator;
  typedef typename Delaunay_graph::Vertex_circulator  Dual_vertex_circulator;
  typedef typename Delaunay_graph::Face_circulator    Dual_face_circulator;

  typedef typename Delaunay_graph::Finite_vertices_iterator
  Dual_vertices_iterator;

  typedef typename Delaunay_graph::Finite_faces_iterator
  Dual_faces_iterator;

  typedef typename Delaunay_graph::Finite_edges_iterator
  Dual_edges_iterator;
  typedef typename Delaunay_graph::All_edges_iterator
  All_dual_edges_iterator;

 protected:
  // TYPES FOR THE DEGENERACY TESTERS
  typedef typename Adaptation_policy::Has_site_inserter  Has_site_inserter;
  typedef typename Adaptation_policy::Has_site_remover   Has_site_remover;

  typedef typename Adaptation_policy::Edge_rejector
  Edge_rejector;

  typedef typename Adaptation_policy::Face_rejector
  Face_rejector;

 protected:
  // DEGENERACY TESTER BINDERS
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Edge_rejector_binder<Self>
  Edge_rejector_binder;

  typedef CGAL_VORONOI_DIAGRAM_2_INS::Face_rejector_binder<Self>
  Face_rejector_binder;

  // ITERATORS FOR EDGES
  typedef Filter_iterator<Dual_edges_iterator,Edge_rejector_binder>
  Non_degenerate_edges_iterator;

  typedef CGAL_VORONOI_DIAGRAM_2_INS::Edge_iterator_adaptor
  <Self,Non_degenerate_edges_iterator>
  Edge_iterator_base;

  typedef CGAL_VORONOI_DIAGRAM_2_INS::Edge_validity_tester
  <Self,Edge_iterator_base>
  Edge_validity_tester;

  typedef Filter_iterator<Edge_iterator_base,Edge_validity_tester>
  Valid_edges_iterator;

 public:
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Edge_iterator_adaptor
  <Self,Valid_edges_iterator,Tag_false>
  Edge_iterator;

  typedef CGAL_VORONOI_DIAGRAM_2_INS::Halfedge_iterator_adaptor
  <Self,Edge_iterator>
  Halfedge_iterator;

  // THE HALFEDGE
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Halfedge<Self>     Halfedge;

 protected:
  // ITERATORS FOR FACES
  typedef Filter_iterator<Dual_vertices_iterator,Face_rejector_binder>
  Non_degenerate_faces_iterator;

 public:
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Face_iterator_adaptor
  <Self,Non_degenerate_faces_iterator>
  Face_iterator;

  // THE FACE
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Face<Self>         Face;

 protected:
  // ITERATORS FOR VERTICES
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Vertex_validity_tester<Self>
  Vertex_validity_tester;

  typedef Filter_iterator<Dual_faces_iterator,Vertex_validity_tester>
  Non_degenerate_vertices_iterator;

 public:
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Vertex_iterator_adaptor
  <Self,Non_degenerate_vertices_iterator>
  Vertex_iterator;

  // THE VERTEX
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Vertex<Self>       Vertex;

 public:
  // HANDLES
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Handle_adaptor<Halfedge>  Halfedge_handle;
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Handle_adaptor<Vertex>    Vertex_handle;
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Handle_adaptor<Face>      Face_handle;

  // CIRCULATORS
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Halfedge_around_vertex_circulator_adaptor
  <Halfedge>
  Halfedge_around_vertex_circulator;

  typedef CGAL_VORONOI_DIAGRAM_2_INS::Ccb_halfedge_circulator_adaptor
  <Halfedge>
  Ccb_halfedge_circulator;

  // THE BOUNDED AND UNBOUNDED FACES ITERATOR
 protected:
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Bounded_face_tester
  <Self,Non_degenerate_faces_iterator>

  Bounded_face_tester;

  typedef CGAL_VORONOI_DIAGRAM_2_INS::Unbounded_face_tester
  <Self,Non_degenerate_faces_iterator>
  Unbounded_face_tester;

 protected:
  typedef
  Filter_iterator<Non_degenerate_faces_iterator,Bounded_face_tester>
  Unbounded_faces_iterator_base;

  typedef
  Filter_iterator<Non_degenerate_faces_iterator,Unbounded_face_tester>
  Bounded_faces_iterator_base;

 public:
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Face_iterator_adaptor
  <Self,Unbounded_faces_iterator_base>
  Unbounded_faces_iterator;

  typedef CGAL_VORONOI_DIAGRAM_2_INS::Face_iterator_adaptor
  <Self,Bounded_faces_iterator_base>
  Bounded_faces_iterator;

  // THE BOUNDED AND UNBOUNDED HALFEDGES ITERATOR
 protected:
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Bounded_edge_tester
  <Self,Edge_iterator>
  Bounded_edge_tester;

  typedef CGAL_VORONOI_DIAGRAM_2_INS::Unbounded_edge_tester
  <Self,Edge_iterator>
  Unbounded_edge_tester;

 protected:
  typedef
  Filter_iterator<Edge_iterator,Bounded_edge_tester>
  Unbounded_edges_iterator_base;

  typedef
  Filter_iterator<Edge_iterator,Unbounded_edge_tester>
  Bounded_edges_iterator_base;

 public:
  typedef CGAL_VORONOI_DIAGRAM_2_INS::Halfedge_iterator_adaptor