From cb4a5de56f142603eb63e82f6769616bf5ff058a Mon Sep 17 00:00:00 2001
From: Kai Moritz <kai@juplo.de>
Date: Fri, 17 Feb 2023 14:48:23 +0100
Subject: [PATCH] coutner: 1.2.3 - Simplified topology, using default-serdes
 for all steps

- Defined `JsonSerde` as default for keys and values.
- Configured the `JsonDeserializer` for header-based typing.
- Removed the configuration of specific serdes from all steps of the
  processor-topology, expect the initial step, that needs a `StringSerde`
  for the key.
---
 pom.xml                                       |  2 +-
 .../CounterApplicationConfiguriation.java     | 15 +++++++++---
 .../counter/CounterStreamProcessor.java       | 23 +++----------------
 3 files changed, 16 insertions(+), 24 deletions(-)

diff --git a/pom.xml b/pom.xml
index 15a07c1..cbccc73 100644
--- a/pom.xml
+++ b/pom.xml
@@ -10,7 +10,7 @@
 	</parent>
 	<groupId>de.juplo.kafka.wordcount</groupId>
 	<artifactId>counter</artifactId>
-	<version>1.2.2</version>
+	<version>1.2.3</version>
 	<name>Wordcount-Counter</name>
 	<description>Word-counting stream-processor of the multi-user wordcount-example</description>
 	<properties>
diff --git a/src/main/java/de/juplo/kafka/wordcount/counter/CounterApplicationConfiguriation.java b/src/main/java/de/juplo/kafka/wordcount/counter/CounterApplicationConfiguriation.java
index f1da407..1bcc834 100644
--- a/src/main/java/de/juplo/kafka/wordcount/counter/CounterApplicationConfiguriation.java
+++ b/src/main/java/de/juplo/kafka/wordcount/counter/CounterApplicationConfiguriation.java
@@ -3,7 +3,6 @@ package de.juplo.kafka.wordcount.counter;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.kafka.clients.consumer.ConsumerConfig;
-import org.apache.kafka.common.serialization.Serdes;
 import org.apache.kafka.streams.StreamsConfig;
 import org.apache.kafka.streams.state.KeyValueBytesStoreSupplier;
 import org.apache.kafka.streams.state.Stores;
@@ -12,6 +11,9 @@ import org.springframework.boot.context.properties.EnableConfigurationProperties
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.kafka.support.serializer.JsonDeserializer;
+import org.springframework.kafka.support.serializer.JsonSerde;
+import org.springframework.kafka.support.serializer.JsonSerializer;
 
 import java.util.Properties;
 import java.util.concurrent.CompletableFuture;
@@ -31,8 +33,15 @@ public class CounterApplicationConfiguriation
 
 		propertyMap.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
 		propertyMap.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
-		propertyMap.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.StringSerde.class.getName());
-		propertyMap.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.StringSerde.class.getName());
+		propertyMap.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, JsonSerde.class.getName());
+		propertyMap.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, JsonSerde.class.getName());
+		propertyMap.put(JsonDeserializer.TRUSTED_PACKAGES, Word.class.getPackageName());
+		propertyMap.put(JsonDeserializer.KEY_DEFAULT_TYPE, Word.class.getName());
+		propertyMap.put(JsonDeserializer.VALUE_DEFAULT_TYPE, Word.class.getName());
+		propertyMap.put(
+				JsonDeserializer.TYPE_MAPPINGS,
+				"W:" + Word.class.getName() + "," +
+				"C:" + WordCount.class.getName());
 		propertyMap.put(StreamsConfig.STATE_DIR_CONFIG, "target");
 		if (properties.getCommitInterval() != null)
 			propertyMap.put(StreamsConfig.COMMIT_INTERVAL_MS_CONFIG, properties.getCommitInterval());
diff --git a/src/main/java/de/juplo/kafka/wordcount/counter/CounterStreamProcessor.java b/src/main/java/de/juplo/kafka/wordcount/counter/CounterStreamProcessor.java
index 4cc0c68..d64eb68 100644
--- a/src/main/java/de/juplo/kafka/wordcount/counter/CounterStreamProcessor.java
+++ b/src/main/java/de/juplo/kafka/wordcount/counter/CounterStreamProcessor.java
@@ -8,10 +8,8 @@ import org.apache.kafka.streams.KeyValue;
 import org.apache.kafka.streams.StreamsBuilder;
 import org.apache.kafka.streams.Topology;
 import org.apache.kafka.streams.kstream.KStream;
-import org.apache.kafka.streams.kstream.Materialized;
 import org.apache.kafka.streams.state.KeyValueBytesStoreSupplier;
 import org.apache.kafka.streams.kstream.*;
-import org.springframework.kafka.support.serializer.JsonSerde;
 
 import java.util.Properties;
 
@@ -48,30 +46,15 @@ public class CounterStreamProcessor
 
 		KStream<String, Word> source = builder.stream(
 				inputTopic,
-				Consumed.with(
-						Serdes.String(),
-						new JsonSerde<>(Word.class)
-								.ignoreTypeHeaders()));
+				Consumed.with(Serdes.String(), null));
 
 		source
 				.map((key, word) -> new KeyValue<>(word, word))
-				.groupByKey(Grouped.with(
-						new JsonSerde<>(Word.class)
-								.forKeys()
-								.noTypeInfo(),
-						new JsonSerde<>(Word.class)
-								.noTypeInfo()))
+				.groupByKey()
 				.count(Materialized.as(storeSupplier))
 				.toStream()
 				.map((word, count) -> new KeyValue<>(word, WordCount.of(word, count)))
-				.to(
-						outputTopic,
-						Produced.with(
-								new JsonSerde<>(Word.class)
-										.forKeys()
-										.noTypeInfo(),
-								new JsonSerde<>(WordCount.class)
-										.noTypeInfo()));
+				.to(outputTopic);
 
 		Topology topology = builder.build();
 		log.info("\n\n{}", topology.describe());
-- 
2.20.1