diff -r 6777f0b0e7b5 -r 0a7d604a9763 src/lemon/concept/graph_component.h
--- a/src/lemon/concept/graph_component.h	Fri Jan 28 15:19:34 2005 +0000
+++ b/src/lemon/concept/graph_component.h	Fri Jan 28 15:37:08 2005 +0000
@@ -297,12 +297,26 @@
       ///
       int id(const Node&) const { return -1;}
 
-      /// Gives back an unique integer id for the Edge. 
+      /// \brief Gives back the node by the unique id.
+      ///
+      /// Gives back the node by the unique id.
+      /// If the graph does not contain node with the given id
+      /// then the result of the function is undetermined. 
+      Node fromId(int id, Node) const { return INVALID;}
 
+      /// \brief Gives back an unique integer id for the Edge. 
+      ///
       /// Gives back an unique integer id for the Edge. 
       ///
       int id(const Edge&) const { return -1;}
 
+      /// \brief Gives back the edge by the unique id.
+      ///
+      /// Gives back the edge by the unique id.
+      /// If the graph does not contain edge with the given id
+      /// then the result of the function is undetermined. 
+      Edge fromId(int id, Edge) const { return INVALID;}
+
       template <typename _Graph>
       struct Constraints {
 
@@ -311,9 +325,11 @@
 	  typename _Graph::Node node;
 	  int nid = graph.id(node);
 	  nid = graph.id(node);
+	  node = graph.fromId(nid, Node());
 	  typename _Graph::Edge edge;
 	  int eid = graph.id(edge);
 	  eid = graph.id(edge);
+	  edge = graph.fromId(eid, Edge());
 	}
 
 	const _Graph& graph;