code: private void initAttributesAndElements(String... propertyNames)
          {
          for (String propertyName : propertyNames)
              {
              Property property = new Property(propertyName);
              if (property.isAttribute())
                  {
                  m_attributes.add(property);
                  }
              else
                  {
                  m_elements.add(property);
                  }
              }
          }
docs: Parses user-specified property names and determines which properties
  should be written out as attributes and which as child elements.
  
  @param propertyNames  property names