Hi Jason, The topic is used in *FlinkKafkaConsumer*, following the *KafkaDeserializationSchema* and then *Properties*.
https://ci.apache.org/projects/flink/flink-docs-release-1.9/api/java/org/apache/flink/streaming/connectors/kafka/FlinkKafkaConsumer.html new FlinkKafkaConsumer(kafkaTopic, new MessageDeserializer, kafkaProperties) ... class MessageDeserializer extends KafkaDeserializationSchema[GenericRecord] { On Thu, Jan 23, 2020 at 1:20 AM Jason Kania <jason.ka...@ymail.com> wrote: > Hello, > > I was looking for documentation in 1.9.1 on how to create implementations > of the KafkaSerializationSchema and KafkaDeserializationSchema > interfaces. I have created implementations in the past for the > SerializationSchema and DeserializationSchema interface. Unfortunately, I > can find no examples and the code contains no documentation for this > purpose but some information appears missing. > > Can someone please answer the following: > > 1) When creating a ProducerRecord with the > KafkaSerializationSchema.serialize() > method, how is the topic String supposed to be obtained by the implementing > class? All of the constructors require that the topic be specified, but the > topic is not passed in. Is there another interface that should be > implemented to get the topic or get a callback? Or is expected that the > topic has to be fixed in the interface's implementation class? Some of the > constructors also ask for a partition. Again, where is this information > expected to come from? > > 2) The interfaces specify that ConsumerRecord<byte[], byte[]> is received > and ProducerRecord<byte[], byte[]> is to be generated. What are the 2 > byte arrays referencing in the type definitions? > > Thanks, > > Jason >
