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

   1 package de.juplo.kafka.wordcount.splitter;
   2
   3 import org.springframework.boot.SpringApplication;
   4 import org.springframework.boot.autoconfigure.SpringBootApplication;
   5 import org.springframework.boot.context.properties.EnableConfigurationProperties;
   6 import org.springframework.context.annotation.Bean;
   7 import org.springframework.expression.Expression;
   8 import org.springframework.expression.ExpressionParser;
   9 import org.springframework.expression.common.LiteralExpression;
  10 import org.springframework.expression.spel.standard.SpelExpressionParser;
  11 import org.springframework.integration.annotation.ServiceActivator;
  12 import org.springframework.integration.annotation.Transformer;
  13 import org.springframework.integration.config.EnableIntegration;
  14 import org.springframework.integration.core.MessageProducer;
  15 import org.springframework.integration.kafka.inbound.KafkaMessageDrivenChannelAdapter;
  16 import org.springframework.integration.kafka.outbound.KafkaProducerMessageHandler;
  17 import org.springframework.integration.transformer.HeaderEnricher;
  18 import org.springframework.integration.transformer.support.ExpressionEvaluatingHeaderValueMessageProcessor;
  19 import org.springframework.integration.transformer.support.HeaderValueMessageProcessor;
  20 import org.springframework.kafka.core.ConsumerFactory;
  21 import org.springframework.kafka.core.KafkaTemplate;
  22 import org.springframework.kafka.listener.ContainerProperties;
  23 import org.springframework.kafka.listener.KafkaMessageListenerContainer;
  24 import org.springframework.integration.kafka.channel.SubscribableKafkaChannel;
  25 import org.springframework.kafka.config.KafkaListenerContainerFactory;
  26 import org.springframework.kafka.listener.AbstractMessageListenerContainer;
  27 import org.springframework.messaging.MessageHandler;
  28
  29 import java.util.HashMap;
  30 import java.util.Map;
  31
  32
  33 @SpringBootApplication
  34 @EnableConfigurationProperties(SplitterApplicationProperties.class)
  35 @EnableIntegration
  36 public class SplitterApplication
  37 {
  38         @Bean
  39         MessageProducer messageProducer(
  40                         KafkaMessageListenerContainer<String, String> messageListenerContainer)
  41         {
  42                 KafkaMessageDrivenChannelAdapter<String, String> adapter =
  43                                 new KafkaMessageDrivenChannelAdapter(messageListenerContainer);
  44                 adapter.setOutputChannelName("kafka-in");
  45                 return adapter;
  46         }
  47
  48         @Bean
  49         @Transformer(inputChannel = "kafka-in", outputChannel = "recordings")
  50         public HeaderEnricher kafkaInHeaderEnricher()
  51         {
  52                 Map<String, HeaderValueMessageProcessor<?>> headersToAdd = new HashMap<>();
  53                 Expression expression =
  54                                 new SpelExpressionParser().parseExpression("headers['kafka_receivedMessageKey']");
  55                 headersToAdd.put(
  56                                 "key",
  57                                 new ExpressionEvaluatingHeaderValueMessageProcessor<>(expression, String.class));
  58                 HeaderEnricher enricher = new HeaderEnricher(headersToAdd);
  59                 return enricher;
  60         }
  61
  62         @Bean
  63         KafkaMessageListenerContainer<String, String> messageListenerContainer(
  64                         ConsumerFactory<String,String> consumerFactory,
  65                         SplitterApplicationProperties properties)
  66         {
  67                 return
  68                                 new KafkaMessageListenerContainer<>(
  69                                                 consumerFactory,
  70                                                 new ContainerProperties(properties.getInputTopic()));
  71         }
  72
  73         @Bean
  74         SubscribableKafkaChannel recordings(
  75                         KafkaTemplate<String, String> kafkaTemplate,
  76                         KafkaListenerContainerFactory<AbstractMessageListenerContainer<String, String>> containerFactory)
  77         {
  78                 SubscribableKafkaChannel channel =
  79                                 new SubscribableKafkaChannel(kafkaTemplate, containerFactory, "channel-recordings");
  80                 channel.setGroupId("recordings");
  81                 return channel;
  82         }
  83
  84         @Bean
  85         @ServiceActivator(inputChannel = "words")
  86         MessageHandler handler(
  87                         KafkaTemplate<String, String> kafkaTemplate,
  88                         SplitterApplicationProperties properties)
  89         {
  90                 KafkaProducerMessageHandler<String, String> handler =
  91                                 new KafkaProducerMessageHandler<>(kafkaTemplate);
  92                 handler.setTopicExpression(new LiteralExpression(properties.getOutputTopic()));
  93                 final ExpressionParser parser = new SpelExpressionParser();
  94                 Expression expression = parser.parseExpression("headers['key']");
  95                 handler.setMessageKeyExpression(expression);
  96                 return handler;
  97         }
  98
  99         @Bean
 100         SubscribableKafkaChannel words(
 101                         KafkaTemplate<String, String> kafkaTemplate,
 102                         KafkaListenerContainerFactory<AbstractMessageListenerContainer<String, String>> containerFactory)
 103         {
 104                 SubscribableKafkaChannel channel =
 105                                 new SubscribableKafkaChannel(kafkaTemplate, containerFactory, "channel-words");
 106                 channel.setGroupId("words");
 107                 return channel;
 108         }
 109
 110         public static void main(String[] args)
 111         {
 112                 SpringApplication.run(SplitterApplication.class, args);
 113         }
 114 }