1 package de.juplo.kafka;
3 import lombok.RequiredArgsConstructor;
4 import lombok.extern.slf4j.Slf4j;
5 import org.apache.kafka.clients.consumer.Consumer;
6 import org.apache.kafka.clients.consumer.ConsumerRecord;
7 import org.apache.kafka.clients.consumer.ConsumerRecords;
8 import org.apache.kafka.common.errors.WakeupException;
10 import java.time.Duration;
11 import java.util.Arrays;
12 import java.util.concurrent.Callable;
16 @RequiredArgsConstructor
17 public class SimpleConsumer implements Callable<Integer>
19 private final String id;
20 private final String topic;
21 private final Consumer<String, Message> consumer;
22 private final MessageHandler messageHandler;
24 private long consumed = 0;
32 log.info("{} - Subscribing to topic {}", id, topic);
33 consumer.subscribe(Arrays.asList(topic));
37 ConsumerRecords<String, Message> records =
38 consumer.poll(Duration.ofSeconds(1));
40 log.info("{} - Received {} messages", id, records.count());
41 for (ConsumerRecord<String, Message> record : records)
52 catch(WakeupException e)
54 log.info("{} - Consumer was signaled to finish its work", id);
59 log.error("{} - Unexpected error: {}, unsubscribing!", id, e.toString());
60 consumer.unsubscribe();
65 log.info("{} - Closing the KafkaConsumer", id);
67 log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
71 private void handleRecord(
79 log.info("{} - {}: {}/{} - {}={}", id, offset, topic, partition, key, value);
80 messageHandler.handle(key, value);