implement operator << for ObjectFactory.

src/core/object-factory.cc

@@ -70,7 +70,7 @@ ObjectFactory::Create (void) const
 
 std::ostream & operator << (std::ostream &os, const ObjectFactory &factory)
 {
-  // XXX
+  os << factory.m_tid.GetName () << "[" << factory.m_parameters.SerializeToString () << "]";
   return os;
 }
 std::istream & operator >> (std::istream &is, ObjectFactory &factory)

src/core/object-factory.h

@@ -76,6 +76,9 @@ public:
 
   ATTRIBUTE_HELPER_HEADER_1 (ObjectFactory);
 private:
+  friend std::ostream & operator << (std::ostream &os, const ObjectFactory &factory);
+  friend std::istream & operator >> (std::istream &is, ObjectFactory &factory);
+
   TypeId m_tid;
   AttributeList m_parameters;
 };