static Map<String, CachedValue<XmlEntityDecl>> getCachingMap(final PsiElement targetElement) {
    Map<String, CachedValue<XmlEntityDecl>> map = targetElement.getUserData(XML_ENTITY_DECL_MAP);
    if (map == null){
      map = new HashMap<>();
      targetElement.putUserData(XML_ENTITY_DECL_MAP, map);
    }
    return map;
  }
static Map<String, CachedValue<XmlEntityDecl>> getCachingMap(final PsiElement targetElement)