Spring-Boot Version des Simple-Consumer

[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 eaa9566..0e37686 100644 (file)
--- a/src/main/java/de/juplo/kafka/SimpleConsumer.java
+++ b/src/main/java/de/juplo/kafka/SimpleConsumer.java
@@ -1,64 +1,40 @@
 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.locks.Condition;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReentrantLock;
 
 
 @Slf4j
-public class SimpleConsumer
+@RequiredArgsConstructor
+public class SimpleConsumer implements Runnable
 {
-  private long consumed = 0;
-  private KafkaConsumer<String, String> consumer;
-  private Lock lock = new ReentrantLock();
-  private Condition stopped = lock.newCondition();
-
-
-  public SimpleConsumer()
-  {
-    // tag::create[]
-    Properties props = new Properties();
-    props.put("bootstrap.servers", ":9092");
-    props.put("group.id", "my-consumer"); // << Used for Offset-Commits
-    // end::create[]
-    props.put("auto.offset.reset", "earliest");
-    // tag::create[]
-    props.put("key.deserializer", StringDeserializer.class.getName());
-    props.put("value.deserializer", StringDeserializer.class.getName());
+  private final String id;
+  private final String topic;
+  private final Consumer<String, String> consumer;
 
-    KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
-    // end::create[]
-    this.consumer = consumer;
-  }
+  private long consumed = 0;
 
 
+  @Override
   public void run()
   {
-    String id = "C";
-
     try
     {
-      log.info("{} - Subscribing to topic test", id);
-      consumer.subscribe(Arrays.asList("test"));
+      log.info("{} - Subscribing to topic {}", id, topic);
+      consumer.subscribe(Arrays.asList(topic));
 
-      // tag::loop[]
       while (true)
       {
         ConsumerRecords<String, String> records =
             consumer.poll(Duration.ofSeconds(1));
 
-        // Do something with the data...
-        // end::loop[]
         log.info("{} - Received {} messages", id, records.count());
         for (ConsumerRecord<String, String> record : records)
         {
@@ -73,59 +49,22 @@ public class SimpleConsumer
               record.value()
           );
         }
-        // tag::loop[]
       }
-      // end::loop[]
     }
     catch(WakeupException e)
     {
-      log.info("{} - RIIING!", id);
+      log.info("{} - Consumer was signaled to finish its work", id);
     }
     catch(Exception e)
     {
-      log.error("{} - Unexpected error: {}", id, e.toString());
+      log.error("{} - Unexpected error: {}, unsubscribing!", id, e.toString());
+      consumer.unsubscribe();
     }
     finally
     {
-      this.lock.lock();
-      try
-      {
-        log.info("{} - Closing the KafkaConsumer", id);
-        consumer.close();
-        log.info("{} - DONE!");
-        stopped.signal();
-      }
-      finally
-      {
-        this.lock.unlock();
-        log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
-      }
+      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
-  {
-    SimpleConsumer instance = new SimpleConsumer();
-
-    Runtime.getRuntime().addShutdownHook(new Thread(() ->
-    {
-      instance.lock.lock();
-      try
-      {
-        instance.consumer.wakeup();
-        instance.stopped.await();
-      }
-      catch (InterruptedException e)
-      {
-        log.warn("Interrrupted while waiting for the consumer to stop!", e);
-      }
-      finally
-      {
-        instance.lock.unlock();
-      }
-    }));
-
-    instance.run();
-  }
 }