code: @SuppressWarnings("unchecked")
      public static Single<Set<String>> keys(CacheConfigBean cacheConfigBean, String pattern) {
          return SingleRxXian.call(CacheService.CACHE_SERVICE, "cacheKeys", new JSONObject() {{
              put("cacheConfig", cacheConfigBean);
              put("pattern", pattern);
          }}).map(response -> {
              response.throwExceptionIfNotSuccess();
              if (response.getData() instanceof Set) {
                  return (Set<String>) response.getData();
              } else
                  return new HashSet<String>() {{
                      addAll(response.dataToTypedList(String.class));
                  }};
          });
      }
docs: get the keys who's value matches the pattern
  
  @param cacheConfigBean the data source of the cache
  @param pattern         the pattern
  @return the keys