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. 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. --tim On Tue, Apr 19, 2011 at 10:46 AM, Steve Ferris <[email protected]>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: [email protected] > 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 > <[email protected]>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: [email protected] >> 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=2721441
