splitter: 1.0.0 - splits up the recorded sentences into words

[demos/kafka/wordcount] / src / main / java / de / juplo / kafka / wordcount / splitter / SplitterStreamProcessor.java

diff --git a/src/main/java/de/juplo/kafka/wordcount/splitter/SplitterStreamProcessor.java b/src/main/java/de/juplo/kafka/wordcount/splitter/SplitterStreamProcessor.java
new file mode 100644 (file)
index 0000000..7218d6f
--- /dev/null
+++ b/src/main/java/de/juplo/kafka/wordcount/splitter/SplitterStreamProcessor.java
@@ -0,0 +1,77 @@
+package de.juplo.kafka.wordcount.splitter;
+
+import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.apache.kafka.common.serialization.Serdes;
+import org.apache.kafka.streams.KafkaStreams;
+import org.apache.kafka.streams.StreamsBuilder;
+import org.apache.kafka.streams.StreamsConfig;
+import org.apache.kafka.streams.kstream.KStream;
+import org.springframework.boot.SpringApplication;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.stereotype.Component;
+
+import javax.annotation.PostConstruct;
+import javax.annotation.PreDestroy;
+import java.util.Arrays;
+import java.util.Properties;
+import java.util.concurrent.CompletableFuture;
+import java.util.regex.Pattern;
+
+import static org.apache.kafka.streams.errors.StreamsUncaughtExceptionHandler.StreamThreadExceptionResponse.SHUTDOWN_CLIENT;
+
+
+@Slf4j
+@Component
+public class SplitterStreamProcessor
+{
+       final static Pattern PATTERN = Pattern.compile("\\W+");
+
+       public final KafkaStreams streams;
+
+
+       public SplitterStreamProcessor(
+                       SplitterApplicationProperties properties,
+                       ConfigurableApplicationContext context)
+       {
+               StreamsBuilder builder = new StreamsBuilder();
+
+               KStream<String, String> source = builder.stream(properties.getInputTopic());
+               source
+                               .flatMapValues(sentence -> Arrays.asList(PATTERN.split(sentence)))
+                               .to(properties.getOutputTopic());
+
+               Properties props = new Properties();
+               props.put(StreamsConfig.APPLICATION_ID_CONFIG, properties.getApplicationId());
+               props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, properties.getBootstrapServer());
+               props.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
+               props.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
+               props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
+
+               streams = new KafkaStreams(builder.build(), props);
+               streams.setUncaughtExceptionHandler((Throwable e) ->
+               {
+                       log.error("Unexpected error!", e);
+                       CompletableFuture.runAsync(() ->
+                       {
+                               log.info("Stopping application...");
+                               SpringApplication.exit(context, () -> 1);
+                       });
+                       return SHUTDOWN_CLIENT;
+               });
+       }
+
+       @PostConstruct
+       public void start()
+       {
+               log.info("Starting Stream-Processor");
+               streams.start();
+       }
+
+       @PreDestroy
+       public void stop()
+       {
+               log.info("Stopping Stream-Processor");
+               streams.close();
+       }
+}