From: Kai Moritz <kai@juplo.de>
Date: Sun, 6 Apr 2025 10:03:36 +0000 (+0200)
Subject: `ExampleConsumer` in `DeadLetterConsumer` umbenannt -- MOVE
X-Git-Tag: consumer/nodlt--2026-03-20--19-06~25
X-Git-Url: https://juplo.de/gitweb/?a=commitdiff_plain;h=e7f63ed0be5f885608e4d4d25e4c3ff20a4f6cb8;p=demos%2Fkafka%2Ftraining

`ExampleConsumer` in `DeadLetterConsumer` umbenannt -- MOVE
---

diff --git a/src/main/java/de/juplo/kafka/DeadLetterConsumer.java b/src/main/java/de/juplo/kafka/DeadLetterConsumer.java
new file mode 100644
index 00000000..0c06b10f
--- /dev/null
+++ b/src/main/java/de/juplo/kafka/DeadLetterConsumer.java
@@ -0,0 +1,134 @@
+package de.juplo.kafka;
+
+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.common.errors.WakeupException;
+import org.springframework.context.SmartLifecycle;
+
+import java.time.Duration;
+import java.util.Arrays;
+
+
+@Slf4j
+public class ExampleConsumer implements Runnable, SmartLifecycle
+{
+  private final String id;
+  private final String topic;
+  private final Consumer<String, String> consumer;
+
+  private Thread workerThread;
+  private volatile boolean running = false;
+  private long consumed = 0;
+
+
+  public ExampleConsumer(
+    String clientId,
+    String topic,
+    Consumer<String, String> consumer)
+  {
+    this.id = clientId;
+    this.topic = topic;
+    this.consumer = consumer;
+  }
+
+  @Override
+  public synchronized void start()
+  {
+    if (running)
+    {
+      log.info("{} - Already running!", id);
+      return;
+    }
+    running = true;
+    workerThread = new Thread(this, "ExampleConsumer Worker-Thread");
+    workerThread.start();
+  }
+
+
+  @Override
+  public void run()
+  {
+    try
+    {
+      log.info("{} - Subscribing to topic {}", id, topic);
+      consumer.subscribe(Arrays.asList(topic));
+
+      while (true)
+      {
+        ConsumerRecords<String, String> records = consumer.poll(Duration.ofSeconds(1));
+
+        log.info("{} - Received {} messages", id, records.count());
+        for (ConsumerRecord<String, String> record : records)
+        {
+          handleRecord(
+            record.topic(),
+            record.partition(),
+            record.offset(),
+            record.key(),
+            record.value());
+        }
+      }
+    }
+    catch(WakeupException e)
+    {
+      log.info("{} - Consumer was signaled to finish its work", id);
+    }
+    catch(Exception e)
+    {
+      log.error("{} - Unexpected error, unsubscribing!", id, e);
+      consumer.unsubscribe();
+    }
+    finally
+    {
+      log.info("{} - Closing the KafkaConsumer", id);
+      consumer.close();
+      log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
+    }
+  }
+
+  private void handleRecord(
+    String topic,
+    Integer partition,
+    Long offset,
+    String key,
+    String value)
+  {
+    consumed++;
+    log.info("{} - partition={}-{}, offset={}: {}={}", id, topic, partition, offset, key, value);
+  }
+
+
+  @Override
+  public boolean isRunning()
+  {
+    return running;
+  }
+
+  @Override
+  public synchronized void stop()
+  {
+    if (!running)
+    {
+      log.info("{} - Not running!", id);
+      return;
+    }
+
+    running = false;
+
+    log.info("{} - Waking up the consumer", id);
+    consumer.wakeup();
+
+    log.info("{} - Joining the worker thread", id);
+    try
+    {
+      workerThread.join();
+    }
+    catch (InterruptedException e)
+    {
+      Thread.currentThread().interrupt();
+      log.error("{} - Interrupted while waiting for worker thread", id, e);
+    }
+  }
+}
diff --git a/src/main/java/de/juplo/kafka/ExampleConsumer.java b/src/main/java/de/juplo/kafka/ExampleConsumer.java
deleted file mode 100644
index 0c06b10f..00000000
--- a/src/main/java/de/juplo/kafka/ExampleConsumer.java
+++ /dev/null
@@ -1,134 +0,0 @@
-package de.juplo.kafka;
-
-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.common.errors.WakeupException;
-import org.springframework.context.SmartLifecycle;
-
-import java.time.Duration;
-import java.util.Arrays;
-
-
-@Slf4j
-public class ExampleConsumer implements Runnable, SmartLifecycle
-{
-  private final String id;
-  private final String topic;
-  private final Consumer<String, String> consumer;
-
-  private Thread workerThread;
-  private volatile boolean running = false;
-  private long consumed = 0;
-
-
-  public ExampleConsumer(
-    String clientId,
-    String topic,
-    Consumer<String, String> consumer)
-  {
-    this.id = clientId;
-    this.topic = topic;
-    this.consumer = consumer;
-  }
-
-  @Override
-  public synchronized void start()
-  {
-    if (running)
-    {
-      log.info("{} - Already running!", id);
-      return;
-    }
-    running = true;
-    workerThread = new Thread(this, "ExampleConsumer Worker-Thread");
-    workerThread.start();
-  }
-
-
-  @Override
-  public void run()
-  {
-    try
-    {
-      log.info("{} - Subscribing to topic {}", id, topic);
-      consumer.subscribe(Arrays.asList(topic));
-
-      while (true)
-      {
-        ConsumerRecords<String, String> records = consumer.poll(Duration.ofSeconds(1));
-
-        log.info("{} - Received {} messages", id, records.count());
-        for (ConsumerRecord<String, String> record : records)
-        {
-          handleRecord(
-            record.topic(),
-            record.partition(),
-            record.offset(),
-            record.key(),
-            record.value());
-        }
-      }
-    }
-    catch(WakeupException e)
-    {
-      log.info("{} - Consumer was signaled to finish its work", id);
-    }
-    catch(Exception e)
-    {
-      log.error("{} - Unexpected error, unsubscribing!", id, e);
-      consumer.unsubscribe();
-    }
-    finally
-    {
-      log.info("{} - Closing the KafkaConsumer", id);
-      consumer.close();
-      log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
-    }
-  }
-
-  private void handleRecord(
-    String topic,
-    Integer partition,
-    Long offset,
-    String key,
-    String value)
-  {
-    consumed++;
-    log.info("{} - partition={}-{}, offset={}: {}={}", id, topic, partition, offset, key, value);
-  }
-
-
-  @Override
-  public boolean isRunning()
-  {
-    return running;
-  }
-
-  @Override
-  public synchronized void stop()
-  {
-    if (!running)
-    {
-      log.info("{} - Not running!", id);
-      return;
-    }
-
-    running = false;
-
-    log.info("{} - Waking up the consumer", id);
-    consumer.wakeup();
-
-    log.info("{} - Joining the worker thread", id);
-    try
-    {
-      workerThread.join();
-    }
-    catch (InterruptedException e)
-    {
-      Thread.currentThread().interrupt();
-      log.error("{} - Interrupted while waiting for worker thread", id, e);
-    }
-  }
-}