public static boolean isPropertyRef(
     final PsiLiteralExpression expression, final String key, final String resourceBundleName) {
   if (resourceBundleName == null) {
     return !PropertiesImplUtil.findPropertiesByKey(expression.getProject(), key).isEmpty();
   } else {
     final List<PropertiesFile> propertiesFiles =
         propertiesFilesByBundleName(resourceBundleName, expression);
     boolean containedInPropertiesFile = false;
     for (PropertiesFile propertiesFile : propertiesFiles) {
       containedInPropertiesFile |= propertiesFile.findPropertyByKey(key) != null;
     }
     return containedInPropertiesFile;
   }
 }