'Flink TypeInfo Java Generics
I want my Flink app to deserialize data from a Kafka topic either to Flink stream of ConsumerRecord<byte[], byte[]> or a Flink stream of Tuple2<byte[], byte[]> using the Flink org.apache.flink.api.java.tuple.Tuple2 class.
With both options I can't get a getProducedType implementation that compiles.
public class KafkaNOOPDeserialization implements KafkaDeserializationSchema<ConsumerRecord<byte[], byte[]>> {
@Override
public boolean isEndOfStream(ConsumerRecord<byte[], byte[]> nextElement) {
return false;
}
@Override
public ConsumerRecord<byte[], byte[]> deserialize(ConsumerRecord<byte[], byte[]> record) throws Exception {
return record;
}
@Override
public TypeInformation<ConsumerRecord<byte[], byte[]>> getProducedType() {
// This provides TypeInformation<ConsumerRecord>
// It needs TypeInformation<ConsumerRecord<byte[], byte[]>>
var typeInfo = TypeExtractor.getForClass(ConsumerRecord.class);
// This hard cast won't compile
return (TypeInformation<ConsumerRecord<byte[], byte[]>>) typeInfo;
}
}
public class KafkaByteArrayTupleDeserializer implements KafkaDeserializationSchema<Tuple2<byte[], byte[]>> {
@Override
public boolean isEndOfStream(Tuple2<byte[], byte[]> nextElement) {
return false;
}
@Override
public Tuple2<byte[], byte[]> deserialize(ConsumerRecord<byte[], byte[]> record) throws Exception {
return new Tuple2(record.key(), record.value());
}
@Override
public TypeInformation<Tuple2<byte[], byte[]>> getProducedType() {
// This provides TupleTypeInfo<Tuple>
// It needs TupleTypeInfo<Tuple2<byte[], byte[]>>
var typeInfo = TupleTypeInfo.getBasicAndBasicValueTupleTypeInfo(
byte[].class, byte[].class);
// Hard cast won't compile
return (TypeInformation<Tuple2<byte[], byte[]>>) typeInfo;
}
}
Sources
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Source: Stack Overflow
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