code: public Object get(String name, PageFlowContextActivator activator)
      {
          assert (name != null) : "Parameter 'name' must not be null";
          assert (activator != null) : "Parameter 'activator' must not be null";
  
          Object ret = _contexts.get(name);
          if (ret == null) {
              ret = activator.activate();
              _contexts.put(name,ret);
          }
          return ret;
      }
docs: This method will lookup a named object and return it.  The object is
  looked up by name.  If the object doesn't exist, the activator object is
  called to create a new instance of the object before it is returned.
  @param name The name of the object to return
  @param activator An <code>PageFlowContextActivator</code> that will create the new object if
  it doesn't exist.
  @return The object stored by the name.