public String[] getCandidateAttributeNamesForSchemaReferences() {
    return new String[] {REF_ATTR_NAME,TYPE_ATTR_NAME, BASE_ATTR_NAME,NAME_ATTR_NAME, SUBSTITUTION_GROUP_ATTR_NAME,MEMBER_TYPES_ATTR_NAME,
      VALUE_ATTR_NAME, ITEM_TYPE_ATTR_NAME};
  }
public String[] getCandidateAttributeNamesForSchemaReferences()