counter: 1.2.0 - Service reads/writes using `JsonSerde`

- First working version of a refined topology, that reads and writes
  key and value with the `JsonSerde`.
- This topology expects and writes all data as JSON, except the key
  of the incomming messages.
- All used Serdes are directly configured in the topology.

diff --git a/pom.xml b/pom.xml
index 3b72889..ccdd0fc 100644 (file)
--- a/pom.xml
+++ b/pom.xml
@@ -10,7 +10,7 @@
        </parent>
        <groupId>de.juplo.kafka.wordcount</groupId>
        <artifactId>counter</artifactId>
-       <version>1.1.11</version>
+       <version>1.2.0</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/CounterStreamProcessor.java b/src/main/java/de/juplo/kafka/wordcount/counter/CounterStreamProcessor.java
index 4002df2..324e424 100644 (file)
--- a/src/main/java/de/juplo/kafka/wordcount/counter/CounterStreamProcessor.java
+++ b/src/main/java/de/juplo/kafka/wordcount/counter/CounterStreamProcessor.java
@@ -1,8 +1,8 @@
 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.common.serialization.Serdes;
 import org.apache.kafka.streams.KafkaStreams;
 import org.apache.kafka.streams.KeyValue;
 import org.apache.kafka.streams.StreamsBuilder;
@@ -10,6 +10,8 @@ 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;
 
@@ -44,27 +46,44 @@ public class CounterStreamProcessor
        {
                StreamsBuilder builder = new StreamsBuilder();
 
-               KStream<String, String> source = builder.stream(inputTopic);
+               KStream<String, Word> source = builder.stream(
+                               inputTopic,
+                               Consumed.with(
+                                               Serdes.String(),
+                                               new JsonSerde<>(Word.class)
+                                                               .ignoreTypeHeaders()));
+
                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);
-                                       }
-                               })
-                               .groupByKey()
-                               .count(Materialized.as(storeSupplier))
-                               .mapValues(value->Long.toString(value))
+                               .map((key, word) -> new KeyValue<>(word, word))
+                               .groupByKey(Grouped.with(
+                                               new JsonSerde<>(Word.class)
+                                                               .forKeys()
+                                                               .noTypeInfo(),
+                                               new JsonSerde<>(Word.class)
+                                                               .noTypeInfo()))
+                               .count(Materialized
+                                               .<Word,Long>as(storeSupplier)
+                                               .withKeySerde(
+                                                               new JsonSerde<>(Word.class)
+                                                                               .forKeys()
+                                                                               .noTypeInfo())
+                                               .withValueSerde(
+                                                               Serdes.Long()))
                                .toStream()
-                               .to(outputTopic);
+                               .map((word, count) -> new KeyValue<>(word, WordCount.of(word.getUser(), word.getWord(), count)))
+                               .to(
+                                               outputTopic,
+                                               Produced.with(
+                                                               new JsonSerde<>(Word.class)
+                                                                               .forKeys()
+                                                                               .noTypeInfo(),
+                                                               new JsonSerde<>(WordCount.class)
+                                                                               .noTypeInfo()));
+
+               Topology topology = builder.build();
+               log.info("\n\n{}", topology.describe());
 
-               return builder.build();
+               return topology;
        }
 
        public void start()

diff --git a/src/main/java/de/juplo/kafka/wordcount/counter/Key.java b/src/main/java/de/juplo/kafka/wordcount/counter/Key.java
deleted file mode 100644 (file)
index 1e00dca..0000000
--- a/src/main/java/de/juplo/kafka/wordcount/counter/Key.java
+++ /dev/null
@@ -1,11 +0,0 @@
-package de.juplo.kafka.wordcount.counter;
-
-import lombok.Value;
-
-
-@Value(staticConstructor = "of")
-public class Key
-{
-  private final String username;
-  private final String word;
-}

diff --git a/src/main/java/de/juplo/kafka/wordcount/counter/Word.java b/src/main/java/de/juplo/kafka/wordcount/counter/Word.java
new file mode 100644 (file)
index 0000000..4aa5ee2
--- /dev/null
+++ b/src/main/java/de/juplo/kafka/wordcount/counter/Word.java
@@ -0,0 +1,17 @@
+package de.juplo.kafka.wordcount.counter;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+
+@AllArgsConstructor(staticName = "of")
+@NoArgsConstructor
+@Data
+@JsonIgnoreProperties(ignoreUnknown = true)
+public class Word
+{
+  private String user;
+  private String word;
+}

diff --git a/src/main/java/de/juplo/kafka/wordcount/counter/WordCount.java b/src/main/java/de/juplo/kafka/wordcount/counter/WordCount.java
new file mode 100644 (file)
index 0000000..44ccb2d
--- /dev/null
+++ b/src/main/java/de/juplo/kafka/wordcount/counter/WordCount.java
@@ -0,0 +1,12 @@
+package de.juplo.kafka.wordcount.counter;
+
+import lombok.Value;
+
+
+@Value(staticConstructor = "of")
+public class WordCount
+{
+  String user;
+  String word;
+  long count;
+}

diff --git a/src/test/java/de/juplo/kafka/wordcount/counter/TestData.java b/src/test/java/de/juplo/kafka/wordcount/counter/TestData.java
index dc3bcec..8ff7022 100644 (file)
--- a/src/test/java/de/juplo/kafka/wordcount/counter/TestData.java
+++ b/src/test/java/de/juplo/kafka/wordcount/counter/TestData.java
@@ -12,37 +12,37 @@ class TestData
        {
                consumer.accept(
                                "peter",
-                               "Hallo");
+                               "{\"user\":\"peter\",\"word\":\"Hallo\"}");
                consumer.accept(
                                "klaus",
-                               "Müsch");
+                               "{\"user\":\"klaus\",\"word\":\"Müsch\"}");
                consumer.accept(
                                "peter",
-                               "Welt");
+                               "{\"user\":\"peter\",\"word\":\"Welt\"}");
                consumer.accept(
                                "klaus",
-                               "Müsch");
+                               "{\"user\":\"klaus\",\"word\":\"Müsch\"}");
                consumer.accept(
                                "klaus",
-                               "s");
+                               "{\"user\":\"klaus\",\"word\":\"s\"}");
                consumer.accept(
                                "peter",
-                               "Boäh");
+                               "{\"user\":\"peter\",\"word\":\"Boäh\"}");
                consumer.accept(
                                "peter",
-                               "Welt");
+                               "{\"user\":\"peter\",\"word\":\"Welt\"}");
                consumer.accept(
                                "peter",
-                               "Boäh");
+                               "{\"user\":\"peter\",\"word\":\"Boäh\"}");
                consumer.accept(
                                "klaus",
-                               "s");
+                               "{\"user\":\"klaus\",\"word\":\"s\"}");
                consumer.accept(
                                "peter",
-                               "Boäh");
+                               "{\"user\":\"peter\",\"word\":\"Boäh\"}");
                consumer.accept(
                                "klaus",
-                               "s");
+                               "{\"user\":\"klaus\",\"word\":\"s\"}");
        }
 
        static void assertExpectedResult(List<Message> receivedMessages)
@@ -69,37 +69,37 @@ class TestData
        static Message[] expectedMessages =
        {
                        Message.of(
-                                       "{\"username\":\"peter\",\"word\":\"Hallo\"}",
-                                       "1"),
+                                       "{\"user\":\"peter\",\"word\":\"Hallo\"}",
+                                       "{\"user\":\"peter\",\"word\":\"Hallo\",\"count\":1}"),
                        Message.of(
-                                       "{\"username\":\"klaus\",\"word\":\"Müsch\"}",
-                                       "1"),
+                                       "{\"user\":\"klaus\",\"word\":\"Müsch\"}",
+                                       "{\"user\":\"klaus\",\"word\":\"Müsch\",\"count\":1}"),
                        Message.of(
-                                       "{\"username\":\"peter\",\"word\":\"Welt\"}",
-                                       "1"),
+                                       "{\"user\":\"peter\",\"word\":\"Welt\"}",
+                                       "{\"user\":\"peter\",\"word\":\"Welt\",\"count\":1}"),
                        Message.of(
-                                       "{\"username\":\"klaus\",\"word\":\"Müsch\"}",
-                                       "2"),
+                                       "{\"user\":\"klaus\",\"word\":\"Müsch\"}",
+                                       "{\"user\":\"klaus\",\"word\":\"Müsch\",\"count\":2}"),
                        Message.of(
-                                       "{\"username\":\"klaus\",\"word\":\"s\"}",
-                                       "1"),
+                                       "{\"user\":\"klaus\",\"word\":\"s\"}",
+                                       "{\"user\":\"klaus\",\"word\":\"s\",\"count\":1}"),
                        Message.of(
-                                       "{\"username\":\"peter\",\"word\":\"Boäh\"}",
-                                       "1"),
+                                       "{\"user\":\"peter\",\"word\":\"Boäh\"}",
+                                       "{\"user\":\"peter\",\"word\":\"Boäh\",\"count\":1}"),
                        Message.of(
-                                       "{\"username\":\"peter\",\"word\":\"Welt\"}",
-                                       "2"),
+                                       "{\"user\":\"peter\",\"word\":\"Welt\"}",
+                                       "{\"user\":\"peter\",\"word\":\"Welt\",\"count\":2}"),
                        Message.of(
-                                       "{\"username\":\"peter\",\"word\":\"Boäh\"}",
-                                       "2"),
+                                       "{\"user\":\"peter\",\"word\":\"Boäh\"}",
+                                       "{\"user\":\"peter\",\"word\":\"Boäh\",\"count\":2}"),
                        Message.of(
-                                       "{\"username\":\"klaus\",\"word\":\"s\"}",
-                                       "2"),
+                                       "{\"user\":\"klaus\",\"word\":\"s\"}",
+                                       "{\"user\":\"klaus\",\"word\":\"s\",\"count\":2}"),
                        Message.of(
-                                       "{\"username\":\"peter\",\"word\":\"Boäh\"}",
-                                       "3"),
+                                       "{\"user\":\"peter\",\"word\":\"Boäh\"}",
+                                       "{\"user\":\"peter\",\"word\":\"Boäh\",\"count\":3}"),
                        Message.of(
-                                       "{\"username\":\"klaus\",\"word\":\"s\"}",
-                                       "3"),
+                                       "{\"user\":\"klaus\",\"word\":\"s\"}",
+                                       "{\"user\":\"klaus\",\"word\":\"s\",\"count\":3}"),
        };
 }