counter: 1.3.1 - Refined `CounterStreamProcessor` (DRY for type-mapping)

[demos/kafka/wordcount] / src / main / java / de / juplo / kafka / wordcount / counter / CounterStreamProcessor.java

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..2304e55 100644 (file)
--- 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);
@@ -108,17 +114,17 @@ public class CounterStreamProcessor
 
        private static String typeMappingsConfig()
        {
-               return typeMappings()
-                               .entrySet()
-                               .stream()
-                               .map(entry -> entry.getKey() + ":" + entry.getValue().getName())
-                               .collect(Collectors.joining(","));
+               return typeMappingsConfig(Word.class, WordCounter.class);
        }
 
-       private static Map<String, Class> typeMappings()
+       public static String typeMappingsConfig(Class wordClass, Class wordCounterClass)
        {
                return Map.of(
-                               "word", Word.class,
-                               "counter", WordCounter.class);
+                                               "word", wordClass,
+                                               "counter", wordCounterClass)
+                               .entrySet()
+                               .stream()
+                               .map(entry -> entry.getKey() + ":" + entry.getValue().getName())
+                               .collect(Collectors.joining(","));
        }
 }