Apply generic to deserialize in Kafka using Flink - apache-kafka

Question

I am trying to deserialize the object to process the logic in Flink.
Since the records are consumed via Kafka so I used the KafkaDeserialization class.
When the new type of the object is added, I need to add the deserialize class as below.
//Existing deserialize class
class ADeserialize {
extends KafkaDeserializationSchema[TypeAClass] {
val mapper: ObjectMapper = new ObjectMapper
override def isEndOfStream(nextElement: TypeAClass): Boolean = false
override def deserialize(record: ConsumerRecord[Array[Byte], Array[Byte]]): TypeAClass = {
val jsonNode = mapper.readValue(value, classOf[JsonNode])
}
}
override def getProducedType: TypeInformation[TypeAClass] = Types.CASE_CLASS[TypeAClass]
}
//Newly added deserialize class
class BDeserialize {
extends KafkaDeserializationSchema[TypeBClass] {
val mapper: ObjectMapper = new ObjectMapper
override def isEndOfStream(nextElement: TypeBClass): Boolean = false
override def deserialize(record: ConsumerRecord[Array[Byte], Array[Byte]]): TypeBClass = {
val jsonNode = mapper.readValue(value, classOf[JsonNode])
}
}
override def getProducedType: TypeInformation[TypeBClass] = Types.CASE_CLASS[TypeBClass]
}
As you can see, if there are different sources added, then I need to create many times which generates the duplicated sources. To prevent this issue, I think that convering the sources into generic one is idea. But I simply failed to convert it using KafkaDeserializationSchema. My flink version is 1.11 since it is legacy.
Any help will be appreciated Thanks.

Answer 1

What You want is something like :
class MyJsonDeserializationSchema[T](implicit typeInfo: TypeInformation[T) extends KafkaDeserializationSchema[T] {
val mapper: ObjectMapper = new ObjectMapper
override def isEndOfStream(nextElement: T): Boolean = false
override def deserialize(record: ConsumerRecord[Array[Byte], Array[Byte]]): T = {
val jsonNode = mapper.readValue(value, classOf[T])
}
}
override def getProducedType: TypeInformation[T] = typeInfo
}