diff --git a/src/core/object-factory.cc b/src/core/object-factory.cc
index ebdf5e20c..95409d414 100644
--- a/src/core/object-factory.cc
+++ b/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)
diff --git a/src/core/object-factory.h b/src/core/object-factory.h
index 5bb0fd40b..50cb6ee4e 100644
--- a/src/core/object-factory.h
+++ b/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;
 };