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[demos/kafka/training] / src / main / java / de / juplo / kafka / SimpleConsumer.java

diff --git a/src/main/java/de/juplo/kafka/SimpleConsumer.java b/src/main/java/de/juplo/kafka/SimpleConsumer.java
index cab2fb8..8e557c2 100644 (file)
--- a/src/main/java/de/juplo/kafka/SimpleConsumer.java
+++ b/src/main/java/de/juplo/kafka/SimpleConsumer.java
@@ -1,52 +1,35 @@
 package de.juplo.kafka;
 
+import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.clients.consumer.Consumer;
 import org.apache.kafka.clients.consumer.ConsumerRecord;
 import org.apache.kafka.clients.consumer.ConsumerRecords;
-import org.apache.kafka.clients.consumer.KafkaConsumer;
 import org.apache.kafka.common.errors.WakeupException;
-import org.apache.kafka.common.serialization.StringDeserializer;
 
 import java.time.Duration;
 import java.util.Arrays;
-import java.util.Properties;
+import java.util.concurrent.Callable;
 
 
 @Slf4j
-public class SimpleConsumer
+@RequiredArgsConstructor
+public class SimpleConsumer implements Callable<Integer>
 {
   private final String id;
   private final String topic;
-  private final KafkaConsumer<String, String> consumer;
+  private final Consumer<String, String> consumer;
 
-  private volatile boolean running = false;
   private long consumed = 0;
 
-  public SimpleConsumer(String broker, String topic, String groupId, String clientId)
-  {
-    Properties props = new Properties();
-    props.put("bootstrap.servers", broker);
-    props.put("group.id", groupId); // ID für die Offset-Commits
-    props.put("client.id", clientId); // Nur zur Wiedererkennung
-    props.put("auto.offset.reset", "earliest"); // Von Beginn an lesen
-    props.put("partition.assignment.strategy", "org.apache.kafka.clients.consumer.CooperativeStickyAssignor");
-    props.put("key.deserializer", StringDeserializer.class.getName());
-    props.put("value.deserializer", StringDeserializer.class.getName());
-
-    consumer = new KafkaConsumer<>(props);
-
-    this.topic = topic;
-    this.id = clientId;
-  }
-
 
-  public void run()
+  @Override
+  public Integer call()
   {
     try
     {
-      log.info("{} - Subscribing to topic test", id);
-      consumer.subscribe(Arrays.asList("test"));
-      running = true;
+      log.info("{} - Subscribing to topic {}", id, topic);
+      consumer.subscribe(Arrays.asList(topic));
 
       while (true)
       {
@@ -56,81 +39,42 @@ public class SimpleConsumer
         log.info("{} - Received {} messages", id, records.count());
         for (ConsumerRecord<String, String> record : records)
         {
-          consumed++;
-          log.info(
-              "{} - {}: {}/{} - {}={}",
-              id,
-              record.offset(),
-              record.topic(),
-              record.partition(),
-              record.key(),
-              record.value()
-          );
+          handleRecord(
+            record.topic(),
+            record.partition(),
+            record.offset(),
+            record.key(),
+            record.value());
         }
       }
     }
     catch(WakeupException e)
     {
       log.info("{} - Consumer was signaled to finish its work", id);
+      return 0;
     }
     catch(Exception e)
     {
-      log.error("{} - Unexpected error: {}", id, e.toString());
+      log.error("{} - Unexpected error: {}, unsubscribing!", id, e.toString());
+      consumer.unsubscribe();
+      return 1;
     }
     finally
     {
-      running = false;
       log.info("{} - Closing the KafkaConsumer", id);
       consumer.close();
       log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
     }
   }
 
-
-  public static void main(String[] args) throws Exception
+  private void handleRecord(
+    String topic,
+    Integer partition,
+    Long offset,
+    String key,
+    Message value)
   {
-    String broker = ":9092";
-    String topic = "test";
-    String groupId = "my-group";
-    String clientId = "DEV";
-
-    switch (args.length)
-    {
-      case 4:
-        clientId = args[3];
-      case 3:
-        groupId = args[2];
-      case 2:
-        topic = args[1];
-      case 1:
-        broker = args[0];
-    }
-
-
-    SimpleConsumer instance = new SimpleConsumer(broker, topic, groupId, clientId);
-
-    Runtime.getRuntime().addShutdownHook(new Thread(() ->
-    {
-      instance.consumer.wakeup();
-
-      while (instance.running)
-      {
-        log.info("Waiting for main-thread...");
-        try
-        {
-          Thread.sleep(1000);
-        }
-        catch (InterruptedException e) {}
-      }
-      log.info("Shutdown completed.");
-    }));
-
-    log.info(
-        "Running SimpleConsumer: broker={}, topic={}, group-id={}, client-id={}",
-        broker,
-        topic,
-        groupId,
-        clientId);
-    instance.run();
+    consumed++;
+    log.info("{} - {}: {}/{} - {}={}", id, offset, topic, partition, key, value);
   }
 }