Are optional fields possible?

[Tim Robertson]

Hi all,

Is it possible in the schema to indicate that a filed is optional?

I have things like:

          {"name": "userId", "type": "string", "default": null},
          {
                "name": "level",
                "type":
                {
                        "name": "LEVEL_TYPES",
                        "type": "enum",
                        "symbols" : ["DEBUG", "INFO", "WARN", "ERROR"]
                },
                "default": 0
          },

and Java serliazation code:

                HttpTransceiver client = new HttpTransceiver(server);
                LogEvent proxy = (LogEvent)
SpecificRequestor.getClient(LogEvent.class, client);
                Event e = new Event();
                e.level=LEVEL_TYPES.DEBUG;
                ... more setters
                proxy.log(e);

but I seem to have to set a value to every field in the schema, or else I get:

Exception in thread "main" java.lang.NullPointerException
        at 
org.apache.avro.specific.SpecificDatumWriter.writeEnum(SpecificDatumWriter.java:54)
        at 
org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:63)
        at 
org.apache.avro.generic.GenericDatumWriter.writeRecord(GenericDatumWriter.java:89)
        at 
org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:62)
        at 
org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:55)
        at 
org.apache.avro.specific.SpecificRequestor.writeRequest(SpecificRequestor.java:69)
        at org.apache.avro.ipc.Requestor.request(Requestor.java:109)
        at 
org.apache.avro.specific.SpecificRequestor.invoke(SpecificRequestor.java:52)
        at $Proxy0.log(Unknown Source)
        at org.gbif.portalanalytics.client.GBIFLogger.info(GBIFLogger.java:41)
        at org.gbif.portalanalytics.client.GBIFLogger.main(GBIFLogger.java:67)

Is it expected to have to have a value on each field?
For Enums this means I would need a NULL in the Enum explicitly I think.

Thanks for any pointers!
Tim