From 0648885ec026d7434561060dc7edb703efea6853 Mon Sep 17 00:00:00 2001
From: Kai Moritz <kai@juplo.de>
Date: Tue, 11 Jun 2024 20:41:30 +0200
Subject: [PATCH] query: 2.0.0 - Values are serialized as JSON -- works, still
 startling, but explainable

* Splitting the command ``table()``, that reads the input-topic and
  materializes it as ``KTable()``, into the two statements ``stream()``,
  that reads the input-topic into a ``KStream``, and ``toTable()``, that
  turns the `KStream` into a ``KTable``, the ``JsonSerde``, that is
  specified via ``Consumed.with(..)``, is only used for the serialization
  and deserialization concerning the ``KTable`` -- not the deserialization
  of the values, that are read from the input-topic.
* Hence, the type-mappings does not have to be specified for the
  ``JsonSerde``, resulting in better understandable code.
* __Note__, that the resulting topology does not differe, because the
  DSL is able to combine the effects of the two statements.
---
 .../wordcount/query/QueryStreamProcessor.java  | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/src/main/java/de/juplo/kafka/wordcount/query/QueryStreamProcessor.java b/src/main/java/de/juplo/kafka/wordcount/query/QueryStreamProcessor.java
index 0692652..7dacd4b 100644
--- a/src/main/java/de/juplo/kafka/wordcount/query/QueryStreamProcessor.java
+++ b/src/main/java/de/juplo/kafka/wordcount/query/QueryStreamProcessor.java
@@ -5,7 +5,6 @@ import jakarta.annotation.PreDestroy;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.kafka.common.serialization.Serdes;
 import org.apache.kafka.streams.*;
-import org.apache.kafka.streams.kstream.Consumed;
 import org.apache.kafka.streams.kstream.KStream;
 import org.apache.kafka.streams.kstream.KTable;
 import org.apache.kafka.streams.kstream.Materialized;
@@ -13,11 +12,9 @@ import org.apache.kafka.streams.state.HostInfo;
 import org.apache.kafka.streams.state.KeyValueBytesStoreSupplier;
 import org.apache.kafka.streams.state.QueryableStoreTypes;
 import org.apache.kafka.streams.state.ReadOnlyKeyValueStore;
-import org.springframework.kafka.support.serializer.JsonDeserializer;
 import org.springframework.kafka.support.serializer.JsonSerde;
 
 import java.net.URI;
-import java.util.Map;
 import java.util.Optional;
 import java.util.Properties;
 
@@ -55,18 +52,9 @@ public class QueryStreamProcessor
 	{
 		StreamsBuilder builder = new StreamsBuilder();
 
-		JsonSerde valueSerde = new JsonSerde();
-		valueSerde.configure(Map.of(
-				JsonDeserializer.TYPE_MAPPINGS,
-				"user:" + Key.class.getName() + "," +
-						"ranking:" + Ranking.class.getName() + "," +
-						"userdata:" + User.class.getName() + "," +
-						"userranking:" + UserRanking.class.getName()
-		), false);
-		KTable<String, User> users = builder.table(
-				usersInputTopic,
-				Consumed.with(null, valueSerde.copyWithType(User.class))
-				);
+		KTable<String, User> users = builder
+				.stream(usersInputTopic)
+				.toTable(Materialized.with(null, new JsonSerde().copyWithType(User.class)));
 		KStream<String, Ranking> rankings = builder.stream(rankingInputTopic);
 
 		rankings
-- 
2.20.1