On Jun 27, 2009, at 7:52 PM, Kaspar Fischer wrote:
> Dear list,
>
> Is it correct that Jersey uses whatever connection infrastructure
> the servlet container provides? For instance, if I use Jetty with a
> NIO connector, then Jersey will use this? I suppose the answer is
> yes but I prefer to be on the safe side as I am completely new to
> Jersey...
>
Yes.
Jersey provides integration support with Grizzly, Web-based and lower
Adapter-based.
> Here's the actual code I am using; it's a very simple REST service
> to allow a user to download a movie:
>
The code looks OK. You could probably move the CacheControl creation
to the constructor.
Paul.
> @Path("/movie/media/retrieve/{id: [0-9]+}")
> @Singleton
> public static class MovieMediaRetrieveResource
> {
> @Context
> Request request;
>
> @Inject("movieService")
> private MovieService movieService;
>
> @GET
> @Produces("video/*")
> public Response downloadMedia(@PathParam("id") int mediaId)
> throws IOException
> {
> // Fetch media and check existence
> final Media media = movieService.getMedia(mediaId);
> if (media == null)
> {
> throw new NotFoundException();
> }
>
> // Cache forever, as media files do not change
> CacheControl cacheControl = new CacheControl();
> cacheControl.setMaxAge(12 * 30 * 24 * 3600);
> cacheControl.setSMaxAge(12 * 30 * 24 * 3600);
> cacheControl.setMustRevalidate(false);
>
> final MediaCharacteristics characteristics =
> media.getCharacteristics();
> return JerseyUtils.newStreamingResponse(request, new
> DefaultStreamableResource(characteristics.getFileSize(),
> characteristics.getMimetype(), media.getLastModified())
> {
> public InputStream getStream() throws IOException
> {
> return media.getContentStream();
> }
> }, cacheControl);
> }
> }
>
> Thanks,
> Kaspar
>
> --
> /**
> * A resource for streaming in Jersey that has a last-modified time,
> a content length, and a
> * mime-type.
> */
> public interface StreamableResource
> {
> /**
> * Size of the resource.
> *
> * @return size in bytes of the content returned by {_at_link
> #getStream()}
> */
> public long getSize();
>
> /**
> * Mime-type of the resource.
> *
> * @return mime-type
> */
> public String getMimetype();
>
> /**
> * Returns the last-modified date.
> *
> * @return date of last modification of the resource, used for
> caching
> */
> public Date getLastModified();
>
> /**
> * Returns the stream whose content needs to be streamed.
> *
> * @return stream; will be closed automatically
> * @throws IOException
> */
> public InputStream getStream() throws IOException;
> }
>
> public class JerseyUtils
> {
> /**
> * Checks using the given last-modified timestamp whether the given
> resource needs to be
> * transferred at all and if not, returns an appropriate response;
> if the resource needs to be
> * transferred, an appropriate {_at_link StreamableResourceProvider}
> instance is created and wrapped
> * in a response.
> *
> * @param request
> * request;use
> *
> * <pre>
> * @Context
> * Request request;
> * </pre>
> *
> * in your class to inject the request
> * @param resource
> * the resource to stream
> * @param cacheControl
> * caching strategy
> * @return a response suitable for returning from your REST method
> * @throws IOException
> */
> public static Response newStreamingResponse(Request request,
> StreamableResource resource, CacheControl cacheControl)
> throws IOException
> {
> final Date lastModified = resource.getLastModified();
> ResponseBuilder cachedResponse =
> request.evaluatePreconditions(lastModified);
> if (cachedResponse != null)
> {
> return cachedResponse.build();
> }
>
> // Return an object that streams the data
> return Response.ok(resource,
> resource
> .getMimetype
> ()).lastModified(lastModified).cacheControl(cacheControl).build();
> }
> }
>
> /**
> * A class similar to {_at_link StreamingOutput} but providing to the
> client with the length of the
> * stream's data.
> *
> * @author Kaspar Fischer (hbf)
> */
> @Provider
> public class StreamableResourceProvider implements
> MessageBodyWriter<StreamableResource>
> {
> public boolean isWriteable(Class<?> type, Type genericType,
> Annotation[] annotations, MediaType mediaType)
> {
> return StreamableResource.class.isAssignableFrom(type);
> }
>
> public void writeTo(StreamableResource t, Class<?> type, Type
> genericType, Annotation annotations[],
> MediaType mediaType, MultivaluedMap<String, Object>
> httpHeaders, OutputStream entityStream) throws IOException
> {
> final InputStream stream = t.getStream();
> try
> {
> IOUtils.copy(stream, entityStream);
> }
> finally
> {
> stream.close();
> }
> }
>
> public long getSize(StreamableResource t, Class<?> type, Type
> genericType, Annotation[] annotations,
> MediaType mediaType)
> {
> return t.getSize();
> }
> }
>
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