(Event.class)); writer.create(Event.SCHEMA$, new File("target/datafile-test.avro")); writer.append(getEvent()); writer.close(); } When I don't pass in the Event.class to SpecificDatumWriter (the first test method), the above test fails with the following exception: Not in union ["null", {"type":"enum","name":"Suit","namespace":"foo","symbols":["SPADES","CLUBS","HEARS","DIAMONDS"]}]: SPADES at org.apache.avro.generic.GenericData.resolveUnion(GenericData.java:382) at org.apache.avro.generic.GenericDatumWriter.write( GenericDatumWriter.java:67) at org.apache.avro.generic.GenericDatumWriter.writeRecord( GenericDatumWriter.java:100) at org.apache.avro.generic.GenericDatumWriter.write( GenericDatumWriter.java:62) at org.apache.avro.generic.GenericDatumWriter.write( GenericDatumWriter.java:54) at org.apache.avro.file.DataFileWriter.append(DataFileWriter.java:245) AvroOutputFormat uses the SpecificDatumWriter's default c'tor, so I run into the above exception when using it. Is there some way around this (other than implementing my own OutputFormat that passes along the class?). Thanks, Joe --20cf3056425526bb030497dce022 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable What's the "best" way to represent an optional enum in avro (= in terms of space efficiency, computational efficiency, and readability)? = =A0To be consistent with other optional fields, I was planning to use union= of null and my enum type. =A0The other approach I could see was adding a N= ULL field to the enum -- but then my code would have to initialize the enum= field to null before a write.

I've tried to use union of null and the enum-type, but I= 've run into an issue with this approach when using the AvroOutputForma= t. =A0The following code summarizes my issue:

=A0=A0public void testDataWrite= WithSchema() throws IOException {
=A0=A0 =A0final DataFileWriter<Event> writer =3D
=A0=A0 =A0 =A0new= DataFileWriter<Event>(new SpecificDatumWriter<Event>());
=A0=A0 =A0writer.create(Event.SCHEMA$, new File("target/datafile-tes= t.avro"));
=A0=A0 =A0writer.append(getEvent()); =A0 =A0
=A0=A0 =A0writer.close();=A0=A0}

=
=A0=A0public void testDataWriteWithSchemaWithClass() throws IOException= {
=A0=A0 =A0final DataFileWriter<Event> writer =3D
=A0=A0 =A0 =A0new= DataFileWriter<Event>(new SpecificDatumWriter<Event>(Event.cla= ss));

=A0=A0 =A0writer.create(Event.SCHEMA$, new File("target/d= atafile-test.avro"));
=A0=A0 =A0writer.append(getEvent()); =A0 =A0
=A0=A0 =A0writer.close();=A0=A0}

When I don't pass in the Event.class to = SpecificDatumWriter (the first test method), the above test fails with the = following exception:=A0

Not in union ["null",=A0{"type":"enum",&qu= ot;name":"Suit","namespace":"foo","= symbols":["SPADES","CLUBS","HEARS","= ;DIAMONDS"]}]: SPADES

at org.apache.avro.generic.GenericData.resolveUnion(GenericData.java:382)

at org.apache.avro.generic.GenericDatumWriter.write(= GenericDatumWriter.java:67)

at org.apache.avro.generic.GenericDatumWriter.writeRecord(= GenericDatumWriter.java:100)

at org.apache.avro.generic.GenericDatumWriter.write(= GenericDatumWriter.java:62)

at org.apache.avro.generic.GenericDatumWriter.write(= GenericDatumWriter.java:54)

at org.apache.avro.file.DataFileWriter.append(DataFi= leWriter.java:245)

Avr= oOutputFormat uses the SpecificDatumWriter's default c'tor, so I ru= n into the above exception when using it. =A0Is there some way around this = (other than implementing my own OutputFormat that passes along the class?).=

Thanks,
Joe

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