protected void setRespondCommonHeaders(
     Response response, Resource resource, Response.Status status, Auth auth) {
   response.setStatus(status);
   response.setNonStandardHeader("Server", "milton.io-" + miltonVerson);
   response.setDateHeader(new Date());
   response.setNonStandardHeader("Accept-Ranges", "bytes");
   String etag = eTagGenerator.generateEtag(resource);
   if (etag != null) {
     response.setEtag(etag);
   }
 }
  @Override
  public void respondNotModified(GetableResource resource, Response response, Request request) {
    log.trace("respondNotModified");
    response.setStatus(Response.Status.SC_NOT_MODIFIED);
    response.setDateHeader(new Date());
    String etag = eTagGenerator.generateEtag(resource);
    if (etag != null) {
      response.setEtag(etag);
    }

    // Note that we use a simpler modified date handling here then when
    // responding with content, because in a not-modified situation the
    // modified date MUST be that of the actual resource
    Date modDate = resource.getModifiedDate();
    response.setLastModifiedHeader(modDate);

    cacheControlHelper.setCacheControl(resource, response, request.getAuthorization());
  }
 @Override
 public void respondPartialContent(
     GetableResource resource,
     Response response,
     Request request,
     Map<String, String> params,
     Range range)
     throws NotAuthorizedException, BadRequestException, NotFoundException {
   log.debug("respondPartialContent: " + range.getStart() + " - " + range.getFinish());
   response.setStatus(Response.Status.SC_PARTIAL_CONTENT);
   long st = range.getStart() == null ? 0 : range.getStart();
   long fn;
   Long cl = resource.getContentLength();
   if (range.getFinish() == null) {
     if (cl != null) {
       fn = cl.longValue() - 1; // position is one less then length
     } else {
       log.warn(
           "Couldnt calculate range end position because the resource is not reporting a content length, and no end position was requested by the client: "
               + resource.getName()
               + " - "
               + resource.getClass());
       fn = -1;
     }
   } else {
     fn = range.getFinish();
   }
   response.setContentRangeHeader(st, fn, cl);
   long contentLength = fn - st + 1;
   response.setContentLengthHeader(contentLength);
   response.setDateHeader(new Date());
   String etag = eTagGenerator.generateEtag(resource);
   if (etag != null) {
     response.setEtag(etag);
   }
   String acc = request.getAcceptHeader();
   String ct = resource.getContentType(acc);
   if (ct != null) {
     response.setContentTypeHeader(ct);
   }
   response.setEntity(new GetableResourceEntity(resource, range, params, ct));
 }
 @Override
 public String generateEtag(Resource r) {
   return eTagGenerator.generateEtag(r);
 }