package de.juplo.kafka.wordcount.top10;
-import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
+import de.juplo.kafka.wordcount.avro.Entry;
+import de.juplo.kafka.wordcount.avro.Key;
+import de.juplo.kafka.wordcount.avro.Ranking;
+import io.confluent.kafka.serializers.AbstractKafkaSchemaSerDeConfig;
+import io.confluent.kafka.streams.serdes.avro.SpecificAvroSerde;
import lombok.extern.slf4j.Slf4j;
import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.common.serialization.Serdes;
StreamsBuilder builder = new StreamsBuilder();
builder
- .<String, String>stream(properties.getInputTopic())
- .map((keyJson, countStr) ->
- {
- try
- {
- Key key = mapper.readValue(keyJson, Key.class);
- Long count = Long.parseLong(countStr);
- Entry entry = Entry.of(key.getWord(), count);
- String entryJson = mapper.writeValueAsString(entry);
- return new KeyValue<>(key.getUsername(), entryJson);
- }
- catch (JsonProcessingException e)
- {
- throw new RuntimeException(e);
- }
- })
+ .<Key, Long>stream(properties.getInputTopic())
+ .map((key, count) -> new KeyValue<>(
+ key.getUsername(),
+ Entry.newBuilder().setWord(key.getWord()).setCount(count).build()))
.groupByKey()
.aggregate(
- () -> "{\"entries\" : []}",
- (username, entryJson, rankingJson) ->
- {
- try
- {
- Ranking ranking = mapper.readValue(rankingJson, Ranking.class);
- ranking.add(mapper.readValue(entryJson, Entry.class));
- return mapper.writeValueAsString(ranking);
- }
- catch (JsonProcessingException e)
- {
- throw new RuntimeException(e);
- }
- }
- )
+ () -> Ranking.newBuilder().build(),
+ (username, entry, ranking) -> {
+ ranking.getEntries().add(entry);
+ return ranking;
+ })
.toStream()
.to(properties.getOutputTopic());
Properties props = new Properties();
props.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
- props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
- props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
+ props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass());
+ props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, SpecificAvroSerde.class);
+ props.put(AbstractKafkaSchemaSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG, properties.getSchemaRegistry());
props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
streams = new KafkaStreams(builder.build(), props);