Status

Current state: Accepted

Discussion thread: Link

JIRA: 

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• New class org.apache.kafka.common.serialization.ListSerializer which implements the Serializer<List<T>>ListSerializer<L extends List<T>, T> implements Serializer<L> interface
• New class org.apache.kafka.common.serialization.ListDeserializer which implements Deserializer<List<T>>ListDeserializer<L extends List<T>, T> implements Deserializer<L> interface
• New subclass ListSerde<T>static subclass ListSerde<L extends List<T>, T> extends WrapperSerde<List<T>> in org.apache.kafka.common.serialization.Serdes which creates new serde based on ListSerializer and ListDeserializer classes
• New method public static <T> Serde<List<T>> ListSerde(Class Class<? extends List> listClass, Serde<T> innerSerde) in  in org.apache.kafka.common.serialization.Serdes class

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This KIP proposes adding new ListSerializer and ListDeserializer classes as well as support for the new ListSerde nested class inside the Serdes class. This will allow using List<T> List<L> Serde directly from Consumers, Producers and Streams where <L extends List<T>, T>.

List<T> List<L> serialization and deserialization will be done through repeatedly calling a serializer/deserializer for each entry provided by passed generic T L's Serdeserde. For example, if you want to create List of Strings serde, then serializer/deserializer of Serdes.StringSerde will be used to serialize/deserialize each entry in List<String>.

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ConsumerConfig.class: LIST_KEY_DEERIALIZERDESERIALIZER_INNER_CLASS_CONFIG = "list.key.deserializer.inner"

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