1 package de.juplo.kafka.wordcount.top10;
3 import lombok.extern.slf4j.Slf4j;
4 import org.apache.kafka.streams.*;
5 import org.apache.kafka.streams.kstream.Materialized;
6 import org.apache.kafka.streams.state.KeyValueBytesStoreSupplier;
7 import org.apache.kafka.streams.state.QueryableStoreTypes;
8 import org.apache.kafka.streams.state.ReadOnlyKeyValueStore;
10 import java.util.Properties;
14 public class Top10StreamProcessor
16 public final KafkaStreams streams;
19 public Top10StreamProcessor(
23 KeyValueBytesStoreSupplier storeSupplier)
25 Topology topology = Top10StreamProcessor.buildTopology(
30 streams = new KafkaStreams(topology, props);
33 static Topology buildTopology(
36 KeyValueBytesStoreSupplier storeSupplier)
38 StreamsBuilder builder = new StreamsBuilder();
41 .<Key, Entry>stream(inputTopic)
42 .map((key, entry) -> new KeyValue<>(User.of(key.getUser()), entry))
46 (user, entry, ranking) -> ranking.add(entry),
47 Materialized.as(storeSupplier))
51 Topology topology = builder.build();
52 log.info("\n\n{}", topology.describe());
57 ReadOnlyKeyValueStore<User, Ranking> getStore(String name)
59 return streams.store(StoreQueryParameters.fromNameAndType(name, QueryableStoreTypes.keyValueStore()));
64 log.info("Starting Stream-Processor");
70 log.info("Stopping Stream-Processor");