implemented levelNeighbor (returning true if neighbor on level exists)

and leafNeighbor (returning true, if neighbor exists and is leaf)

Added default implementations for this feature, using the old neighbor
method and inside and outside

[[Imported from SVN: r4466]]

grid/common/intersectioniterator.hh

@@ -205,10 +205,21 @@ namespace Dune
     }
 
     //! @brief return true if intersection is shared with another element.
-    bool neighbor () const
+    bool neighbor () const DUNE_DEPRECATED
     {
       return this->realIterator.neighbor();
     }
+    //! @brief return true if intersection is shared with another element on the same level.
+    bool levelNeighbor () const
+    {
+      return this->realIterator.levelNeighbor();
+    }
+
+    //! @brief return true if intersection is shared with another leaf element.
+    bool leafNeighbor () const
+    {
+      return this->realIterator.leafNeighbor();
+    }
 
     /*! @brief return EntityPointer to the Entity on the inside of this
        intersection. That is the Entity where we started this Iterator.
@@ -394,6 +405,21 @@ namespace Dune
       n /= n.two_norm();
       return n;
     }
+
+    //! default using old neighbor method
+    bool levelNeighbor () const
+    {
+      return (asImp().neighbor()) ?
+             (asImp().outside()->level() == asImp().inside()->level()) : false;
+    }
+
+    //! default using old neighbor method
+    bool leafNeighbor () const
+    {
+      return (asImp().neighbor()) ?
+             (asImp().outside()->isLeaf()) : false;
+    }
+
   private:
     //!  Barton-Nackman trick
     IntersectionIteratorImp<GridImp>& asImp ()

grid/common/intersectioniteratorwrapper.hh

@@ -95,6 +95,12 @@ namespace Dune {
     //! return true if across the intersection a neighbor on this level exists
     bool neighbor () const { return it().neighbor(); }
 
+    //! return true if across the intersection a neighbor on this level exists
+    bool levelNeighbor () const { return it().levelNeighbor(); }
+
+    //! return true if across the intersection a neighbor on this level exists
+    bool leafNeighbor () const { return it().leafNeighbor(); }
+
     //! return information about the Boundary
     int boundaryId () const { return it().boundaryId(); }