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 static final String STORE_NAME= "top10";
18 public final KafkaStreams streams;
21 public Top10StreamProcessor(
25 KeyValueBytesStoreSupplier storeSupplier)
27 Topology topology = Top10StreamProcessor.buildTopology(
32 streams = new KafkaStreams(topology, props);
35 static Topology buildTopology(
38 KeyValueBytesStoreSupplier storeSupplier)
40 StreamsBuilder builder = new StreamsBuilder();
43 .<Key, Entry>stream(inputTopic)
44 .map((key, entry) -> new KeyValue<>(User.of(key.getUser()), entry))
48 (user, entry, ranking) -> ranking.add(entry),
49 Materialized.as(storeSupplier))
53 Topology topology = builder.build();
54 log.info("\n\n{}", topology.describe());
59 ReadOnlyKeyValueStore<User, Ranking> getStore()
61 return streams.store(StoreQueryParameters.fromNameAndType(STORE_NAME, QueryableStoreTypes.keyValueStore()));
66 log.info("Starting Stream-Processor");
72 log.info("Stopping Stream-Processor");