counter: 1.3.0 - (GREEN) Fixed the typing for the state-store

[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 4002df2..64bd619 100644 (file)
--- a/src/main/java/de/juplo/kafka/wordcount/counter/CounterStreamProcessor.java
+++ b/src/main/java/de/juplo/kafka/wordcount/counter/CounterStreamProcessor.java
@@ -1,15 +1,13 @@
 package de.juplo.kafka.wordcount.counter;
 
-import com.fasterxml.jackson.core.JsonProcessingException;
-import com.fasterxml.jackson.databind.ObjectMapper;
 import lombok.extern.slf4j.Slf4j;
-import org.apache.kafka.streams.KafkaStreams;
-import org.apache.kafka.streams.KeyValue;
-import org.apache.kafka.streams.StreamsBuilder;
-import org.apache.kafka.streams.Topology;
+import org.apache.kafka.streams.*;
 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.state.QueryableStoreTypes;
+import org.apache.kafka.streams.state.ReadOnlyKeyValueStore;
+import org.springframework.kafka.support.serializer.JsonSerde;
 
 import java.util.Properties;
 
@@ -17,6 +15,9 @@ import java.util.Properties;
 @Slf4j
 public class CounterStreamProcessor
 {
+       public static final String STORE_NAME = "counter";
+
+
        public final KafkaStreams streams;
 
 
@@ -24,14 +25,12 @@ public class CounterStreamProcessor
                        String inputTopic,
                        String outputTopic,
                        Properties properties,
-                       KeyValueBytesStoreSupplier storeSupplier,
-                       ObjectMapper mapper)
+                       KeyValueBytesStoreSupplier storeSupplier)
        {
                Topology topology = CounterStreamProcessor.buildTopology(
                                inputTopic,
                                outputTopic,
-                               storeSupplier,
-                               mapper);
+                               storeSupplier);
 
                streams = new KafkaStreams(topology, properties);
        }
@@ -39,32 +38,32 @@ public class CounterStreamProcessor
        static Topology buildTopology(
                        String inputTopic,
                        String outputTopic,
-                       KeyValueBytesStoreSupplier storeSupplier,
-                       ObjectMapper mapper)
+                       KeyValueBytesStoreSupplier storeSupplier)
        {
                StreamsBuilder builder = new StreamsBuilder();
 
-               KStream<String, String> source = builder.stream(inputTopic);
+               KStream<User, Word> source = builder.stream(inputTopic);
+
                source
-                               .map((username, word) ->
-                               {
-                                       try
-                                       {
-                                               String key = mapper.writeValueAsString(Key.of(username, word));
-                                               return new KeyValue<>(key, word);
-                                       }
-                                       catch (JsonProcessingException e)
-                                       {
-                                               throw new RuntimeException(e);
-                                       }
-                               })
+                               .map((key, word) -> new KeyValue<>(word, word))
                                .groupByKey()
-                               .count(Materialized.as(storeSupplier))
-                               .mapValues(value->Long.toString(value))
+                               .count(
+                                               Materialized
+                                                               .<Word, Long>as(storeSupplier)
+                                                               .withKeySerde(new JsonSerde<>().copyWithType(Word.class).forKeys()))
                                .toStream()
+                               .map((word, counter) -> new KeyValue<>(word, WordCounter.of(word, counter)))
                                .to(outputTopic);
 
-               return builder.build();
+               Topology topology = builder.build();
+               log.info("\n\n{}", topology.describe());
+
+               return topology;
+       }
+
+       ReadOnlyKeyValueStore<Word, Long> getStore()
+       {
+               return streams.store(StoreQueryParameters.fromNameAndType(STORE_NAME, QueryableStoreTypes.keyValueStore()));
        }
 
        public void start()