JAX-RS How to choose image mimetype? - jersey

Question

Is there any way to select the very best Accept mimetype for image manipulation?
I have a resource looks like this.
#GET
#Produces({"image/jpeg", "image/png"})
public Response readResizedImage(
#Context Request request,
#Context HttpHeaders httpHeaders,
#QueryParam("width") final int width,
#QueryParam("height") final int height) {
final List<Variant> variants = Variant.mediaTypes(
new MediaType("image", "jpeg"), new MediaType("image", "png")).build();
// Why on earth variants is empty?
if (!variants.isEmpty()) {
final Variant variant = request.selectVariant(variants);
LOGGER.log(Level.INFO, "{0}", variant.getMediaType().toString());
}
final List<MediaType> acceptableMediaTypes =
httpHeaders.getAcceptableMediaTypes();
for (MediaType acceptableMediaType : acceptableMediaTypes) {
LOGGER.log(Level.INFO, "acceptableMediaType:{0}/{1}",
new Object[]{acceptableMediaType.getType(),
acceptableMediaType.getSubtype()});
}
return null;
}
I tried this resource with following command.
$ curl -v -H "Accept: */*" \
-H "Accept: image/*;q=0.2" \
-H "Accept: image/jpeg;q=0.5" \
-H "Accept: image/png;q=1.0" \
http://.............
And server prints
acceptableMediaType:image/png
acceptableMediaType:*/*
acceptableMediaType:image/jpeg
acceptableMediaType:image/*
QUESTION:
How can I select a proper (not wildcarded) mime type?
I must have one for manipulating image bytes for re-sizing.

Answer 1

It is easiest if you leave this up to Jersey - i.e. have 2 methods, one producing image/png, other producing image/jpeg. Jersey will call the right one depending on the quality parameter of individual media types in the accept header of the incoming request.