protected <T> Map<Object, T> getValues(final String regionNamePath, Object... keys) {
    try {
      final Region<Object, T> region = getRegion(regionNamePath);
      final Map<Object, T> entries = region.getAll(Arrays.asList(getKeys(regionNamePath, keys)));
      for (Object key : entries.keySet()) {
        @SuppressWarnings("unchecked")
        final T value =
            (T) securityService.postProcess(regionNamePath, key, entries.get(key), false);
        entries.put(key, value);
      }
      return entries;
    } catch (SerializationException se) {
      throw new DataTypeNotSupportedException(
          "The resource identified could not convert into the supported content characteristics (JSON)!",
          se);
    }
  }
AbstractBaseController class contains common functionalities required for other controllers.

@since GemFire 8.0
geode-web-api/src/main/java/org/apache/geode/rest/internal/web/controllers/AbstractBaseController.java