code: @Override
      public boolean isEmpty(boolean includeDiskCache) {
  
          boolean isCacheEmpty = false;
  
          /*
           * Check if the memory cache has entries
           */
          isCacheEmpty = cache.getNumberCacheEntries() == 0;
  
          /*
           * If the memory cache is not empty then we don't need to check the disk cache.
           * If the cache is an instanceof CacheProviderWrapper then we know it's not dynacache so
           * we need to check if it supports disk caching. If it doesn't then we don't need to check
           * if the disk cache is empty.
           */
          if (includeDiskCache && isCacheEmpty) {
              if (cache instanceof CacheProviderWrapper) {
                  if (((CacheProviderWrapper) cache).featureSupport.isDiskCacheSupported()) {
                      isCacheEmpty = cache.getIdsSizeDisk() == 0;
                  }
              } else {
                  // Not an instanceof CacheProviderWrapper so we know it's dynacache and we know
                  // getIdsSizeDisk is implemented.
                  isCacheEmpty = cache.getIdsSizeDisk() == 0;
              }
          }
          return isCacheEmpty;
      }
docs: Returns <tt>true</tt> if this map contains no key-value mappings.
  
  @param includeDiskCache true to check the memory and disk maps; false to check
  the memory map.
  @return <tt>true</tt> if this map contains no key-value mappings.