Hi Tim, many thanks for your help. It's definitely interesting, but unfortunately not useful this time, I think, as that JsonTypeInfo and JsonSubClasses annotations are on the base class, which, in my case, I don't own and even if I did, I don't think I could list all the subclasses GenericJson has.
I've discovered, though, that I can configure the ObjectMapper to add that type information to all objects using 'enableDefaultTyping' https://fasterxml.github.io/jackson-databind/javadoc/2.8/com/fasterxml/jackson/databind/ObjectMapper.html#enableDefaultTyping () Thanks! On Wed, May 9, 2018 at 8:01 PM Tim Robertson <timrobertson...@gmail.com> wrote: > Hi Carlos > > Here is an example of subclassing with Jackson using the @Type annotation > that I did many years ago: > > https://github.com/gbif/gbif-api/tree/master/src/main/java/org/gbif/api/model/registry/eml/temporal > > It decorates the JSON with an extra field ("@Type" in this case) which > instructs the deserializers which Object to instantiate. I'm not sure if > newer Jackson versions have changed. > > I haven't considered if this is appropriate or not in your case, but I > hope this helps with the Jackson bit of your question at least. > > Best wishes, > Tim > > > > > > > > On Wed, May 9, 2018 at 7:02 PM, Carlos Alonso <car...@mrcalonso.com> > wrote: > >> Hi everyone!! >> >> I'm working on BEAM-4257 issue and the approach I'm following is to >> create a new class 'BigQueryInsertError' that also extends 'GenericJson' >> and that contains three keys 'TableRow row', >> 'TableDataInsertAllResponse.InsertErrors error', and 'TableReference ref' >> and use this type as the contained items returned by >> WriteResults.getFailedInserts >> >> I have now to create a Coder for this new type and I'm following the >> TableRowJsonCoder way >> https://github.com/apache/beam/blob/master/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/bigquery/TableRowJsonCoder.java#L34 >> by >> relying on Jackson's ObjectMapper and StringUtf8Encoder. >> >> The problem is that I always get errors when deserialising as it >> deserialises the inner TableRow as a LinkedHashMap and fails when trying to >> assign it. Here you can see the full stacktrace: >> https://pastebin.com/MkUD9L3W >> >> Testing it a bit further I've spotted other GenericJson subclasses that >> cannot be encoded/decoded following that method. For example >> TableDataInsertAllResponse.InsertErrors itself. See the example below: >> >> TableDataInsertAllResponse.InsertErrors err = new >> TableDataInsertAllResponse.InsertErrors().setIndex(0L); >> ObjectMapper mapper = new >> ObjectMapper().disable(SerializationFeature.FAIL_ON_EMPTY_BEANS); >> mapper.readValue(mapper.writeValueAsString(err), >> TableDataInsertAllResponse.InsertErrors.class); >> >> >> Fails with a similar error, but in this case is because it deserialises >> the index into an int: https://pastebin.com/bzXMR3z5 >> >> So a couple of questions here: >> * Which is the appropriate way of encoding/decoding GenericJson >> subclasses? (Maybe this issues can be tackled using Jackson's type >> annotations, but I'm quite a newbie on Jackson and I couldn't figure out >> how) >> * This will (hopefully) be my very first contribution to Apache Beam and >> I'd like to get some feedback/comments/ideas/... on the issue and the >> suggested solution. >> >> Thanks everyone! >> > >
