package de.juplo.kafka.wordcount.top10;
-import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
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.KeyValue;
import org.apache.kafka.streams.StreamsBuilder;
-import org.apache.kafka.streams.StreamsConfig;
-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.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 Top10StreamProcessor
{
- final static Pattern PATTERN = Pattern.compile("\\W+");
-
public final KafkaStreams streams;
public Top10StreamProcessor(
- Top10ApplicationProperties properties,
+ String inputTopic,
+ String outputTopic,
ObjectMapper mapper,
- ConfigurableApplicationContext context)
+ Properties props)
{
StreamsBuilder builder = new StreamsBuilder();
builder
- .<String, String>stream(properties.getInputTopic())
- .map((keyJson, countStr) ->
+ .<Word, WordCount>stream(inputTopic)
+ .map((word, wordCount) ->
{
- try
- {
- Key key = mapper.readValue(keyJson, Key.class);
- Long count = Long.parseLong(countStr);
- Entry entry = Entry.of(key.getWord(), count);
- String entryJson = mapper.writeValueAsString(entry);
- return new KeyValue<>(key.getUsername(), entryJson);
- }
- catch (JsonProcessingException e)
- {
- throw new RuntimeException(e);
- }
+ Entry entry = Entry.of(word.getWord(), wordCount.getCount());
+ return new KeyValue<>(word.getUser(), entry);
})
.groupByKey()
.aggregate(
- () -> "{\"entries\" : []}",
- (username, entryJson, rankingJson) ->
+ () -> new Ranking(),
+ (user, entry, ranking) ->
{
- try
- {
- Ranking ranking = mapper.readValue(rankingJson, Ranking.class);
- ranking.add(mapper.readValue(entryJson, Entry.class));
- return mapper.writeValueAsString(ranking);
- }
- catch (JsonProcessingException e)
- {
- throw new RuntimeException(e);
- }
+ ranking.add(entry);
+ return ranking;
}
)
.toStream()
- .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");
+ .to(outputTopic);
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");