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https://issues.apache.org/jira/browse/AVRO-1870?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15380758#comment-15380758
]
Ali Hashemi commented on AVRO-1870:
-----------------------------------
Oh! You are absolutely right Matt. Thank you.
I am using a 3rd party code in which AvroMsgManager class has a serialize
method and uses GenericDatumWriter().
...
ByteArrayOutputStream out = new ByteArrayOutputStream();
DatumWriter<GenericRecord> writer = new
GenericDatumWriter<>(schema);
Encoder encoder = EncoderFactory.get().binaryEncoder(out,
null);
writer.write(datum, encoder);
...
So, you say that SpecificDatumWriter should have been used? But, I am
serializing objects not classes. Or maybe I am missing something else as well.
> Avro compiler generate JAVA enum interfaces but writeEnum expects
> GenericEnumSymbol
> -----------------------------------------------------------------------------------
>
> Key: AVRO-1870
> URL: https://issues.apache.org/jira/browse/AVRO-1870
> Project: Avro
> Issue Type: Bug
> Components: java
> Affects Versions: 1.8.1
> Reporter: Ali Hashemi
>
> Avro compiler generate an enum JAVA class from an enum Avro type
> and this class is used in the Java class of the records pointing to the enum
> type. However, org.apache.avro.generic.GenericDatumWriter.writeEnum expects a
> GenericEnumSymbol rather than Java Enum!
> This is problem because the class interfaces for Avro messages expect Java
> Enum and not GenericEnumSymbol!
> Consider the following schema:
> TrafficLights.avsc:
> {"namespace": "com.comp.message",
> "type": "record",
> "name": "TrafficLights",
> "fields": [
> {"name": "id", "type": "string"},
> {"name": "signal", "type": "Signals" }
> ]
> }
> Signals.avsc:
> {
> "namespace": "com.comp.message",
> "type": "enum",
> "name":"Signals",
> "symbols" : ["GREEN", "YELLOW", "RED"]
> }
> Using maven-avro-plugin to import "Signals" as an external schema, Avro
> compiler creates the following constructor for TrafficLights class:
> public TrafficLights(java.lang.CharSequence id, com.comp.message.Signals
> signal){...}
> and an Enum class fot the Signals:
> package com.comp.message;
> @SuppressWarnings("all")
> @org.apache.avro.specific.AvroGenerated
> public enum Signals {
> GREEN, YELLOW, RED ;
> public static final org.apache.avro.Schema SCHEMA$ = new
> org.apache.avro.Schema.Parser().parse("{\"type\":\"enum\",\"name\":\"Signals\",\"namespace\":\"com.comp.message\",\"symbols\":[\"GREEN\",\"YELLOW\",\"RED\"]}");
> public static org.apache.avro.Schema getClassSchema() { return SCHEMA$; }
> }
> However, when I try to serialize a TrafficLights message,
> GenericDatumWriter.writeEnum throws an exeception:
> TrafficLights mainTrafficLight = new TrafficLights ("123", Signals.GREEN);
> byte[] msg = new AvroMsgManager( mainTrafficLight .getSchema().toString()
> ).serialize (mainTrafficLight))
> org.apache.avro.AvroTypeException: Not an enum: GREEN
> at
> org.apache.avro.generic.GenericDatumWriter.writeEnum(GenericDatumWriter.java:164)
> at
> org.apache.avro.generic.GenericDatumWriter.writeWithoutConversion(GenericDatumWriter.java:106)
> at
> org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:73)
> at
> org.apache.avro.generic.GenericDatumWriter.writeField(GenericDatumWriter.java:153)
> at
> org.apache.avro.generic.GenericDatumWriter.writeRecord(GenericDatumWriter.java:143)
> at
> org.apache.avro.generic.GenericDatumWriter.writeWithoutConversion(GenericDatumWriter.java:105)
> at
> org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:73)
> at
> org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:60)
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