docs: protected void addResourceRelationRules(Digester digester, String xpath) {
  
          String xp_rels = xpath + N_RELATIONS + "/" + N_RELATION;
          digester.addCallMethod(xp_rels, "addRelation");
          digester.addCallMethod(xp_rels + "/" + N_ID, "setRelationId", 0);
          digester.addCallMethod(xp_rels + "/" + N_PATH, "setRelationPath", 0);
          digester.addCallMethod(xp_rels + "/" + N_TYPE, "setRelationType", 0);
      }