Region<String, String> getQueryStore(final String namePath) {
    return ValidationUtils.returnValueThrowOnNull(getCache().getInternalRegion(namePath),
        new GemfireRestException(String.format("Query store (%1$s) does not exist!", namePath)));
  }
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