code: @Override
      public void init(FilterConfig filterConfig) throws ServletException {
          super.init(filterConfig);
  
          int reloadTime = readInt(filterConfig.getInitParameter(INIT_PARAM_RELOAD_TIME), 0);
  
          this.resetTime = readInt(filterConfig.getInitParameter(INIT_PARAM_RESET_TIME), resetTime);
          this.cacheKeyFormat = readString(filterConfig.getInitParameter(INIT_PARAM_CAHE_KEY_FORMAT), DEFAULT_CACHE_KEY_FORMAT);
  
          lastResetTime = new Date().getTime();
  
          CacheConfig<String, CachedResponse> cacheConfig = new CacheConfig<>();
  
          String providerValue = readString(filterConfig.getInitParameter(INIT_PARAM_CACHE_PROVIDER), null);
  
          if (providerValue != null)
              cacheConfig.setProvider(CacheConfig.CacheProvider.valueOf(providerValue.toUpperCase()));
  
          String cacheHost = filterConfig.getInitParameter(INIT_PARAM_CACHE_HOST);
          cacheConfig.setHostname(cacheHost);
          int cachePort = readInt(filterConfig.getInitParameter(INIT_PARAM_CACHE_PORT), 0);
          cacheConfig.setPortNumber(cachePort);
  
          if (!CacheFactory.isCacheProvider(cache, cacheConfig.getProvider())) {
              try {
                  cache = CacheFactory.getCache(cacheConfig);
              } catch (Exception ex) {
                  LOGGER.debug("Failed to initialize Cache Config: {}. Falling back to default Cache Service.", cacheConfig);
                  cache = CacheFactory.<String, CachedResponse>getDefaultCache();
              }
          }
  
          LOGGER.debug("Cache Filter initialized with: " +
                          "{}:{},\n" +
                          "{}:{},\n" +
                          "{}:{},\n" +
                          "{}:{},\n" +
                          "{}:{}",
                  INIT_PARAM_CACHE_PROVIDER, providerValue,
                  INIT_PARAM_CACHE_HOST, cacheHost,
                  INIT_PARAM_CACHE_PORT, String.valueOf(cachePort),
                  INIT_PARAM_RELOAD_TIME, String.valueOf(reloadTime),
                  INIT_PARAM_RESET_TIME, String.valueOf(resetTime));
      }
docs: eg. "queryString, header=X-Requested-By, parameter=username". URI is always part of key