--- a/examples/wifi-adhoc.cc	Mon Mar 24 10:41:44 2008 -0700
+++ b/examples/wifi-adhoc.cc	Mon Mar 24 10:42:18 2008 -0700
@@ -142,7 +142,7 @@
   mobility.SetPositionAllocator (positionAlloc);
   mobility.SetMobilityModel ("ns3::StaticMobilityModel");
 
-  mobility.Layout (c.Begin (), c.End ());
+  mobility.Layout (c);
 
   PacketSocketAddress destination = PacketSocketAddress ();
   destination.SetProtocol (1);

--- a/examples/wifi-ap.cc	Mon Mar 24 10:41:44 2008 -0700
+++ b/examples/wifi-ap.cc	Mon Mar 24 10:42:18 2008 -0700
@@ -161,8 +161,8 @@
   wifi.Build (ap, channel);
 
   // mobility.
-  mobility.Layout (stas.Begin (), stas.End ());
-  mobility.Layout (ap.Begin (), ap.End ());
+  mobility.Layout (stas);
+  mobility.Layout (ap);
 
   Simulator::Schedule (Seconds (1.0), &AdvancePosition, ap.Get (0));
 

--- a/samples/main-grid-topology.cc	Mon Mar 24 10:41:44 2008 -0700
+++ b/samples/main-grid-topology.cc	Mon Mar 24 10:42:18 2008 -0700
@@ -16,13 +16,10 @@
   CommandLine cmd;
   cmd.Parse (argc, argv);
 
-  std::vector<Ptr<Object> > nodes;
+  NodeContainer nodes;
 
   // create an array of empty nodes for testing purposes 
-  for (uint32_t i = 0; i < 120; i++)
-    {
-      nodes.push_back (CreateObject<Node> ());
-    }
+  nodes.Create (120);
 
   MobilityHelper mobility;
   // setup the grid itself: objects are layed out
@@ -44,13 +41,13 @@
   // finalize the setup by attaching to each object
   // in the input array a position and initializing
   // this position with the calculated coordinates.
-  mobility.Layout (nodes.begin (), nodes.end ());
+  mobility.Layout (nodes);
 
   // iterate our nodes and print their position.
-  for (std::vector<Ptr<Object> >::const_iterator j = nodes.begin ();
-       j != nodes.end (); j++)
+  for (NodeContainer::Iterator j = nodes.Begin ();
+       j != nodes.End (); ++j)
     {
-      Ptr<Object> object = *j;
+      Ptr<Node> object = *j;
       Ptr<MobilityModel> position = object->GetObject<MobilityModel> ();
       NS_ASSERT (position != 0);
       Vector pos = position->GetPosition ();

--- a/samples/main-random-topology.cc	Mon Mar 24 10:41:44 2008 -0700
+++ b/samples/main-random-topology.cc	Mon Mar 24 10:42:18 2008 -0700
@@ -29,11 +29,8 @@
   cmd.Parse (argc, argv);
 
 
-  std::vector<Ptr<Object> > objects;
-  for (uint32_t i = 0; i < 10000; i++)
-    {
-      objects.push_back (CreateObject<Node> ());
-    }
+  NodeContainer c;
+  c.Create (10000);
 
   MobilityHelper mobility;
   mobility.EnableNotifier ();
@@ -42,7 +39,7 @@
                                  "Y", String ("100.0"),
                                  "Rho", String ("Uniform:0:30"));
   mobility.SetMobilityModel ("ns3::StaticMobilityModel");
-  mobility.Layout (objects.begin (), objects.end ());
+  mobility.Layout (c);
 
   Config::Connect ("/NodeList/*/$ns3::MobilityModelNotifier/CourseChange",
                               MakeCallback (&CourseChange));

--- a/samples/main-random-walk.cc	Mon Mar 24 10:41:44 2008 -0700
+++ b/samples/main-random-walk.cc	Mon Mar 24 10:42:18 2008 -0700
@@ -36,10 +36,8 @@
   CommandLine cmd;
   cmd.Parse (argc, argv);
 
-  for (uint32_t i = 0; i < 100; i++)
-    {
-      Ptr<Node> node = CreateObject<Node> ();
-    }
+  NodeContainer c;
+  c.Create (100);
 
   MobilityHelper mobility;
   mobility.EnableNotifier ();
@@ -52,7 +50,7 @@
                              "Time", String ("2s"),
                              "Speed", String ("Constant:1.0"),
                              "Bounds", String ("0:200:0:100"));
-  mobility.Layout (NodeList::Begin (), NodeList::End ());
+  mobility.LayoutAll ();
   Config::Connect ("/NodeList/*/$ns3::MobilityModelNotifier/CourseChange",
                               MakeCallback (&CourseChange));
 

--- a/src/helper/mobility-helper.cc	Mon Mar 24 10:41:44 2008 -0700
+++ b/src/helper/mobility-helper.cc	Mon Mar 24 10:42:18 2008 -0700
@@ -101,9 +101,9 @@
 }
 
 void 
-MobilityHelper::Layout (const std::vector<Ptr<Object> > &objects)
+MobilityHelper::Layout (NodeContainer c)
 {
-  for (std::vector<Ptr<Object> >::const_iterator i = objects.begin (); i != objects.end (); i++)
+  for (NodeContainer::Iterator i = c.Begin (); i != c.End (); ++i)
     {
       Ptr<Object> object = *i;
       Ptr<MobilityModel> model = object->GetObject<MobilityModel> ();
@@ -145,4 +145,10 @@
     }
 }
 
+void 
+MobilityHelper::LayoutAll (void)
+{
+  Layout (NodeContainer::GetGlobal ());
+}
+
 } // namespace ns3

--- a/src/helper/mobility-helper.h	Mon Mar 24 10:41:44 2008 -0700
+++ b/src/helper/mobility-helper.h	Mon Mar 24 10:42:18 2008 -0700
@@ -4,13 +4,17 @@
 #include <vector>
 #include "ns3/object-factory.h"
 #include "ns3/attribute.h"
-#include "position-allocator.h"
+#include "ns3/position-allocator.h"
+#include "node-container.h"
 
 namespace ns3 {
 
 class PositionAllocator;
 class MobilityModel;
 
+/**
+ * \brief assign positions and mobility models to nodes.
+ */
 class MobilityHelper
 {
 public:
@@ -48,10 +52,9 @@
 
   std::string GetMobilityModelType (void) const;
 
-  template <typename T>
-  void Layout (T begin, T end);
+  void Layout (NodeContainer container);
+  void LayoutAll (void);
 private:
-  void Layout (const std::vector<Ptr<Object> > &objects);
 
   std::vector<Ptr<MobilityModel> > m_mobilityStack;
   bool m_notifierEnabled;
@@ -61,21 +64,4 @@
 
 } // namespace ns3
 
-namespace ns3 {
-
-template <typename T>
-void
-MobilityHelper::Layout (T begin, T end)
-{
-  std::vector<Ptr<Object> > objects;
-  for (T i = begin; i != end; i++)
-    {
-      Ptr<Object> object = *i;
-      objects.push_back (object);
-    }
-  Layout (objects);
-}
-
-} // namespace ns3
-
 #endif /* MOBILITY_HELPER_H */