juplo.de Git - demos/kafka/wordcount/blob - src/main/java/de/juplo/kafka/wordcount/counter/CounterStreamProcessor.java

   1 package de.juplo.kafka.wordcount.counter;
   2
   3 import com.fasterxml.jackson.databind.ObjectMapper;
   4 import lombok.extern.slf4j.Slf4j;
   5 import org.apache.kafka.common.serialization.Serdes;
   6 import org.apache.kafka.streams.KafkaStreams;
   7 import org.apache.kafka.streams.KeyValue;
   8 import org.apache.kafka.streams.StreamsBuilder;
   9 import org.apache.kafka.streams.Topology;
  10 import org.apache.kafka.streams.kstream.KStream;
  11 import org.apache.kafka.streams.kstream.Materialized;
  12 import org.apache.kafka.streams.state.KeyValueBytesStoreSupplier;
  13 import org.apache.kafka.streams.kstream.*;
  14 import org.springframework.kafka.support.serializer.JsonSerde;
  15
  16 import java.util.Properties;
  17
  18
  19 @Slf4j
  20 public class CounterStreamProcessor
  21 {
  22         public final KafkaStreams streams;
  23
  24
  25         public CounterStreamProcessor(
  26                         String inputTopic,
  27                         String outputTopic,
  28                         Properties properties,
  29                         KeyValueBytesStoreSupplier storeSupplier,
  30                         ObjectMapper mapper)
  31         {
  32                 Topology topology = CounterStreamProcessor.buildTopology(
  33                                 inputTopic,
  34                                 outputTopic,
  35                                 storeSupplier,
  36                                 mapper);
  37
  38                 streams = new KafkaStreams(topology, properties);
  39         }
  40
  41         static Topology buildTopology(
  42                         String inputTopic,
  43                         String outputTopic,
  44                         KeyValueBytesStoreSupplier storeSupplier,
  45                         ObjectMapper mapper)
  46         {
  47                 StreamsBuilder builder = new StreamsBuilder();
  48
  49                 KStream<String, Word> source = builder.stream(
  50                                 inputTopic,
  51                                 Consumed.with(
  52                                                 Serdes.String(),
  53                                                 new JsonSerde<>(Word.class)
  54                                                                 .ignoreTypeHeaders()));
  55
  56                 source
  57                                 .map((key, word) -> new KeyValue<>(word, word))
  58                                 .groupByKey(Grouped.with(
  59                                                 new JsonSerde<>(Word.class)
  60                                                                 .forKeys()
  61                                                                 .noTypeInfo(),
  62                                                 new JsonSerde<>(Word.class)
  63                                                                 .noTypeInfo()))
  64                                 .count(Materialized.as(storeSupplier))
  65                                 .toStream()
  66                                 .map((word, count) -> new KeyValue<>(word, WordCount.of(word.getUser(), word.getWord(), count)))
  67                                 .to(
  68                                                 outputTopic,
  69                                                 Produced.with(
  70                                                                 new JsonSerde<>(Word.class)
  71                                                                                 .forKeys()
  72                                                                                 .noTypeInfo(),
  73                                                                 new JsonSerde<>(WordCount.class)
  74                                                                                 .noTypeInfo()));
  75
  76                 Topology topology = builder.build();
  77                 log.info("\n\n{}", topology.describe());
  78
  79                 return topology;
  80         }
  81
  82         public void start()
  83         {
  84                 log.info("Starting Stream-Processor");
  85                 streams.start();
  86         }
  87
  88         public void stop()
  89         {
  90                 log.info("Stopping Stream-Processor");
  91                 streams.close();
  92         }
  93 }