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.messaging.MessageHandler;
  25
  26 import java.util.HashMap;
  27 import java.util.Map;
  28
  29
  30 @SpringBootApplication
  31 @EnableConfigurationProperties(SplitterApplicationProperties.class)
  32 @EnableIntegration
  33 public class SplitterApplication
  34 {
  35         @Bean
  36         MessageProducer messageProducer(
  37                         KafkaMessageListenerContainer<String, String> messageListenerContainer)
  38         {
  39                 KafkaMessageDrivenChannelAdapter<String, String> adapter =
  40                                 new KafkaMessageDrivenChannelAdapter(messageListenerContainer);
  41                 adapter.setOutputChannelName("kafka-in");
  42                 return adapter;
  43         }
  44
  45         @Bean
  46         @Transformer(inputChannel = "kafka-in", outputChannel = "recordings")
  47         public HeaderEnricher kafkaInHeaderEnricher()
  48         {
  49                 Map<String, HeaderValueMessageProcessor<?>> headersToAdd = new HashMap<>();
  50                 Expression expression =
  51                                 new SpelExpressionParser().parseExpression("headers['kafka_receivedMessageKey']");
  52                 headersToAdd.put(
  53                                 "key",
  54                                 new ExpressionEvaluatingHeaderValueMessageProcessor<>(expression, String.class));
  55                 HeaderEnricher enricher = new HeaderEnricher(headersToAdd);
  56                 return enricher;
  57         }
  58
  59         @Bean
  60         KafkaMessageListenerContainer<String, String> messageListenerContainer(
  61                         ConsumerFactory<String,String> consumerFactory,
  62                         SplitterApplicationProperties properties)
  63         {
  64                 return
  65                                 new KafkaMessageListenerContainer<>(
  66                                                 consumerFactory,
  67                                                 new ContainerProperties(properties.getInputTopic()));
  68         }
  69
  70         @Bean
  71         @ServiceActivator(inputChannel = "words")
  72         MessageHandler handler(
  73                         KafkaTemplate<String, String> kafkaTemplate,
  74                         SplitterApplicationProperties properties)
  75         {
  76                 KafkaProducerMessageHandler<String, String> handler =
  77                                 new KafkaProducerMessageHandler<>(kafkaTemplate);
  78                 handler.setTopicExpression(new LiteralExpression(properties.getOutputTopic()));
  79                 final ExpressionParser parser = new SpelExpressionParser();
  80                 Expression expression = parser.parseExpression("headers['key']");
  81                 handler.setMessageKeyExpression(expression);
  82                 return handler;
  83         }
  84
  85         public static void main(String[] args)
  86         {
  87                 SpringApplication.run(SplitterApplication.class, args);
  88         }
  89 }