From bdd62b6b906db3b10ae04d2b4c80e6426a90ad7f Mon Sep 17 00:00:00 2001
From: Kai Moritz <kai@juplo.de>
Date: Sun, 16 Jun 2024 21:08:01 +0200
Subject: [PATCH] counter: 1.3.1 - Refined `CounterStreamProcessor`
 (serde-config)

* Refactored the creation of the ``JsonSerde``s, that are used to consume
  the incomming messages.
* All special ``Serdes``, that are used for incomming and outgoing messages,
  are created in separted methods now.
* Removed unnecessary operatorx in the ``Materialized``-configuration for
  the state store (the operator is not necessary, because no headers are
  present, when deserializing from a store).
---
 .../counter/CounterStreamProcessor.java        | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

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 97d460f..c983a25 100644
--- a/src/main/java/de/juplo/kafka/wordcount/counter/CounterStreamProcessor.java
+++ b/src/main/java/de/juplo/kafka/wordcount/counter/CounterStreamProcessor.java
@@ -47,17 +47,13 @@ public class CounterStreamProcessor
 		StreamsBuilder builder = new StreamsBuilder();
 
 		builder
-				.stream(
-						inputTopic,
-						Consumed.with(
-								new JsonSerde<>(User.class),
-								new JsonSerde<>(Word.class)))
+				.stream(inputTopic, Consumed.with(inKeySerde(), inValueSerde()))
 				.map((key, word) -> new KeyValue<>(word, word))
 				.groupByKey()
 				.count(
 						Materialized
 								.<Word, Long>as(storeSupplier)
-								.withKeySerde(new JsonSerde<>().copyWithType(Word.class).forKeys()))
+								.withKeySerde(new JsonSerde<>(Word.class))) // No headers are present: fixed typing is needed!
 				.toStream()
 				.map((word, counter) -> new KeyValue<>(word, WordCounter.of(word, counter)))
 				.to(outputTopic, Produced.with(outKeySerde(), outValueSerde()));
@@ -87,6 +83,16 @@ public class CounterStreamProcessor
 
 
 
+	public static JsonSerde<User> inKeySerde()
+	{
+		return new JsonSerde<>(User.class);
+	}
+
+	public static JsonSerde<Word> inValueSerde()
+	{
+		return new JsonSerde<>(Word.class);
+	}
+
 	public static JsonSerde<Word> outKeySerde()
 	{
 		return serde(true);
-- 
2.20.1