code: public static DecodingResource forEncoding(String contentEncoding, Resource source) throws IOException {
          InputStream stream = decodingStream(contentEncoding, source);
          if (stream == null) {
              return null;
          }
          return new DecodingResource(source, stream);
      }
docs: Returns a DecodingResource that wraps an existing resource with a decompressor for the given
  Content-Encoding.
  
  @param contentEncoding the value of the Content-Encoding header
  @param source the resource to wrap
  @return the new resource or null if the contentEncoding is not supported