juplo.de Git - demos/kafka/wordcount/blob - src/main/java/de/juplo/kafka/wordcount/splitter/SplitterStreamProcessor.java

   1 package de.juplo.kafka.wordcount.splitter;
   2
   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.KStream;
  10 import org.springframework.boot.SpringApplication;
  11 import org.springframework.context.ConfigurableApplicationContext;
  12 import org.springframework.kafka.support.serializer.JsonDeserializer;
  13 import org.springframework.kafka.support.serializer.JsonSerde;
  14 import org.springframework.kafka.support.serializer.JsonSerializer;
  15 import org.springframework.stereotype.Component;
  16
  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;
  23
  24 import static org.apache.kafka.streams.errors.StreamsUncaughtExceptionHandler.StreamThreadExceptionResponse.SHUTDOWN_CLIENT;
  25
  26
  27 @Slf4j
  28 @Component
  29 public class SplitterStreamProcessor
  30 {
  31         final static Pattern PATTERN = Pattern.compile("[^\\p{IsAlphabetic}]+");
  32
  33         public final KafkaStreams streams;
  34
  35
  36         public SplitterStreamProcessor(
  37                         SplitterApplicationProperties properties,
  38                         ConfigurableApplicationContext context)
  39         {
  40                 StreamsBuilder builder = new StreamsBuilder();
  41
  42                 KStream<String, Recording> source = builder.stream(properties.getInputTopic());
  43
  44                 source
  45                                 .flatMapValues(recording -> Arrays
  46                                                         .stream(PATTERN.split(recording.getSentence()))
  47                                                         .map(word -> Word.of(recording.getUser(), word))
  48                                                         .toList())
  49                                 .to(properties.getOutputTopic());
  50
  51                 Properties props = new Properties();
  52                 props.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
  53                 props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
  54                 props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.StringSerde.class.getName());
  55                 props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, JsonSerde.class.getName());
  56                 props.put(JsonDeserializer.TRUSTED_PACKAGES, Recording.class.getName()  );
  57                 props.put(JsonDeserializer.VALUE_DEFAULT_TYPE, Recording.class.getName());
  58                 props.put(JsonSerializer.ADD_TYPE_INFO_HEADERS, false);
  59                 props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
  60
  61                 streams = new KafkaStreams(builder.build(), props);
  62                 streams.setUncaughtExceptionHandler((Throwable e) ->
  63                 {
  64                         log.error("Unexpected error!", e);
  65                         CompletableFuture.runAsync(() ->
  66                         {
  67                                 log.info("Stopping application...");
  68                                 SpringApplication.exit(context, () -> 1);
  69                         });
  70                         return SHUTDOWN_CLIENT;
  71                 });
  72         }
  73
  74         @PostConstruct
  75         public void start()
  76         {
  77                 log.info("Starting Stream-Processor");
  78                 streams.start();
  79         }
  80
  81         @PreDestroy
  82         public void stop()
  83         {
  84                 log.info("Stopping Stream-Processor");
  85                 streams.close();
  86         }
  87 }