1 package de.juplo.kafka.wordcount.splitter;
3 import lombok.extern.slf4j.Slf4j;
4 import org.apache.kafka.clients.consumer.ConsumerConfig;
5 import org.apache.kafka.common.serialization.Serdes;
6 import org.apache.kafka.streams.KafkaStreams;
7 import org.apache.kafka.streams.StreamsBuilder;
8 import org.apache.kafka.streams.StreamsConfig;
9 import org.apache.kafka.streams.kstream.Consumed;
10 import org.apache.kafka.streams.kstream.KStream;
11 import org.apache.kafka.streams.kstream.Produced;
12 import org.springframework.boot.SpringApplication;
13 import org.springframework.context.ConfigurableApplicationContext;
14 import org.springframework.kafka.support.serializer.JsonSerde;
15 import org.springframework.stereotype.Component;
17 import jakarta.annotation.PostConstruct;
18 import jakarta.annotation.PreDestroy;
19 import java.util.Arrays;
20 import java.util.Properties;
21 import java.util.concurrent.CompletableFuture;
22 import java.util.regex.Pattern;
24 import static org.apache.kafka.streams.errors.StreamsUncaughtExceptionHandler.StreamThreadExceptionResponse.SHUTDOWN_CLIENT;
29 public class SplitterStreamProcessor
31 final static Pattern PATTERN = Pattern.compile("\\W+");
33 public final KafkaStreams streams;
36 public SplitterStreamProcessor(
37 SplitterApplicationProperties properties,
38 ConfigurableApplicationContext context)
40 StreamsBuilder builder = new StreamsBuilder();
42 JsonSerde<Recording> recordSerde =
43 new JsonSerde<>(Recording.class).ignoreTypeHeaders();
44 JsonSerde<Word> wordSerde =
45 new JsonSerde<>(Word.class).noTypeInfo();
47 KStream<String, Recording> source = builder.stream(
48 properties.getInputTopic(),
49 Consumed.with(Serdes.String(), recordSerde));
52 .flatMapValues(recording -> Arrays
53 .stream(PATTERN.split(recording.getSentence()))
54 .map(word -> Word.of(recording.getUser(), word))
56 .to(properties.getOutputTopic(), Produced.with(Serdes.String(), wordSerde));
58 Properties props = new Properties();
59 props.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
60 props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
61 props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
62 props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, JsonSerde.class.getName());
63 props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
65 streams = new KafkaStreams(builder.build(), props);
66 streams.setUncaughtExceptionHandler((Throwable e) ->
68 log.error("Unexpected error!", e);
69 CompletableFuture.runAsync(() ->
71 log.info("Stopping application...");
72 SpringApplication.exit(context, () -> 1);
74 return SHUTDOWN_CLIENT;
81 log.info("Starting Stream-Processor");
88 log.info("Stopping Stream-Processor");