> So AMRecord on server -> JSON -> AMRecord on client, but Set<AMRecord> on > server -> JSON -> Set<LinkedHashMap> on client? If so, read on. > > Restlet's JacksonRepresentation uses mapper.readValue(representation, > targetType.class) to do the work, but type parameters are erased, so the > return type is Set.class, and the call becomes > mapper.readValue(representation, Set.class). Jackson does the best it can in > that case; the serialized AMRecord looks like a map.
Excellent, thanks very much. This explains the underlying flow very clearly. > > There are two ways to handle this. If you control the source for AMRecord, > you can tell Jackson (by adding an annotation) to include type information > when it serializes an AMRecord, so that it will be reconstituted properly. If > you don't have access to the source, you'll need to either introduce a holder > type for Set<AMRecord> or write your own subclass of JacksonRepresentation > with custom handling for this case. I have the source to AMRecord, but from reading through this: http://wiki.fasterxml.com/JacksonAnnotations It is unclear to me if the granularity of the annotation is at the class level or if I need one annotation per property? regards Steve > > --tim > > On Tue, Apr 19, 2011 at 10:46 AM, Steve Ferris <steve.fer...@forgerock.com> > wrote: > Hi, > > That is indeed the reason for the class cast exception, but on the server the > Set is populated with AMRecord objects and after the Jackson representation > un-marshalling the AMRecord object has become a LinkedHashMap. > > So there has to be something going on in the Jackson/JSON representation > implementation that prevents my custom class working in a collection, but > fine when it's just on its own. > > regards > Steve > > -- > Steve Ferris : ForgeRock AS : e: steve.fer...@forgerock.com > t: +44 (0)7813 709285 f: +44 (0)7971 042421 w: forgerock.com > OpenAM, the new name for OpenSSO > > On 19 Apr 2011, at 3:40pm, Tim Peierls wrote: > >> A LinkedHashMap is not a Set. Could that explain the class cast exception? >> >> --tim >> >> On Tue, Apr 19, 2011 at 7:13 AM, Steve Ferris <steve.fer...@forgerock.com> >> wrote: >> Hi, >> >> I have a custom class AMRecord which is being handled in an unexpected way. >> >> Two RESTlet calls: >> >> @Get >> public AMRecord read(String id) { >> >> and >> >> @Get >> public Set<AMRecord> readWithSecKey(String id) { >> >> Jackson can cope with AMRecord as the read call works, my client code looks >> like this: >> >> ClientResource resource = new ClientResource(resourceUrl + "/read"); >> ReadResource readResource = resource.wrap(ReadResource.class); >> >> AMRecord record = readResource.read("43478392743"); >> >> I get back an AMRecord instance. >> >> But for the Set, on the client I get a class cast exception >> >> ClientResource resource = new ClientResource(resourceUrl + >> "/readwithseckey"); >> ReadWithSecKeyResource secReadResource = >> resource.wrap(ReadWithSecKeyResource.class); >> >> Set<AMRecord> sessions = >> secReadResource.readWithSecKey("uid=steve,ou=users,o=openam"); >> >> This is because the Set sessions has a LinkedHashMap rather than AMRecord >> entries. The LinkedHashMap is populated with the data from the AMRecord that >> should be present. >> >> Any ideas? >> >> thanks >> Steve >> >> -- >> Steve Ferris : ForgeRock AS : e: steve.fer...@forgerock.com >> t: +44 (0)7813 709285 f: +44 (0)7971 042421 w: forgerock.com >> OpenAM, the new name for OpenSSO >> >> > > ------------------------------------------------------ http://restlet.tigris.org/ds/viewMessage.do?dsForumId=4447&dsMessageId=2721467
