code: public Serializer getSerializer(Class cl)
          throws HessianProtocolException
      {
          if (ObjectName.class.equals(cl)) {
              return new StringValueSerializer();
          }
  
          return null;
      }
docs: Returns the serializer for a class.
  
  @param cl the class of the object that needs to be serialized.
  
  @return a serializer object for the serialization.