The JSON listed is not the form that Avro's json encoder/decoder can
handle. Because the optional fields are unions, Avro's decoder expects you
to first list the type before the values.
Presuming CustomerEmails is an Avro record.
i.e.
{"emails" : { "CustomerEmails" : { "emails": ["[email protected]", "[email protected]"]} },
"transactions": null, "features" : null }
See the spec for more details:
http://avro.apache.org/docs/1.7.7/spec.html#json_encoding
To use the JsonDecoder, you will have to use a JsonEncoder rather than
relying on the toString method (the format of its output is undefined, so
that's probably a good idea anyways).
On Wed, Jun 3, 2015 at 5:20 PM, C 4.5 <[email protected]> wrote:
> Hi All,
>
> I have defined a simple Avro schema for Customer objects. Schema compiles
> OK and don't have any problem.
>
> I am trying to serialize to json string and deserialize into Customer java
> objects but I am not able to.
>
> Please see below:
> [1]: is the full code snippet
> [2]: is the output I obtain
>
> I am using Avro 1.7.7
>
> Customer's schema is flows. Emails are optional.
> {"namespace": "...",
> "type": "record",
> "name": "Customer",
> "fields": [
> {"name": "emails", "type": [ "null", "....CustomerEmails"]},
> {"name": "transactions", "type": [ "null",
> "...CustomerTransactions"]},
> {"name": "features", "type": [ "null", "...CustomerFeatures"]}
> ]
> }
>
> I have researched and tried different things but something seems to escape
> me, this should be a very trivial case to support.
> Hence, I am sure I am just overlooking something that is probably obvious.
>
> Any feedback?
> Thanks a ton
>
> ===[1] code
> // ser
> List<CharSequence> emails = new ArrayList<CharSequence>();
> emails.add("[email protected]");
> emails.add("[email protected]");
>
> CustomerEmails customerEmails = CustomerEmails.newBuilder().
> setEmails(emails).
> build();
>
> Customer customer = Customer.newBuilder().
> setEmails(customerEmails).
> setTransactions(null).
> setFeatures(null).
> build();
>
> String customerJson = customer.toString();
> System.out.println("customer json: " + customerJson);
>
> // de-ser
> JsonDecoder jsonDecoder =
> DecoderFactory.get().jsonDecoder(Customer.getClassSchema(), customerJson);
> SpecificDatumReader<Customer> reader = new
> SpecificDatumReader<Customer>(Customer.class);
> Object obj = reader.read(null, jsonDecoder);
>
> System.out.println("obj=" + obj);
>
> ===[2] output
> customer json: {"emails": {"emails": ["[email protected]", "[email protected]"]},
> "transactions": null, "features": null}
> Exception in thread "main" org.apache.avro.AvroTypeException: Unknown
> union branch emails
> at org.apache.avro.io.JsonDecoder.readIndex(JsonDecoder.java:445)
> at
> org.apache.avro.io.ResolvingDecoder.doAction(ResolvingDecoder.java:290)
> at org.apache.avro.io.parsing.Parser.advance(Parser.java:88)
> at
> org.apache.avro.io.ResolvingDecoder.readIndex(ResolvingDecoder.java:267)
> at
> org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:155)
> at
> org.apache.avro.generic.GenericDatumReader.readField(GenericDatumReader.java:193)
> at
> org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:183)
> at
> org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:151)
> at
> org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:142)
> at com.mytest.Deser.main(Deser.java:79)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke(Method.java:497)
>
--
Sean
