Verbesserungen aus 'stored-state' nach 'rebalance-listener' gemerged

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

diff --git a/src/main/java/de/juplo/kafka/KeyCountingRebalanceListener.java b/src/main/java/de/juplo/kafka/KeyCountingRebalanceListener.java
new file mode 100644 (file)
index 0000000..0ad1f31
--- /dev/null
+++ b/src/main/java/de/juplo/kafka/KeyCountingRebalanceListener.java
@@ -0,0 +1,50 @@
+package de.juplo.kafka;
+
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.clients.consumer.ConsumerRebalanceListener;
+import org.apache.kafka.common.TopicPartition;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+
+
+@RequiredArgsConstructor
+@Slf4j
+public class KeyCountingRebalanceListener implements ConsumerRebalanceListener
+{
+  private final KeyCountingRecordHandler handler;
+  private final String id;
+
+  @Override
+  public void onPartitionsAssigned(Collection<TopicPartition> partitions)
+  {
+    partitions.forEach(tp ->
+    {
+      Integer partition = tp.partition();
+      log.info("{} - adding partition: {}", id, partition);
+      handler.addPartition(partition, new HashMap<>());
+    });
+  }
+
+  @Override
+  public void onPartitionsRevoked(Collection<TopicPartition> partitions)
+  {
+    partitions.forEach(tp ->
+    {
+      Integer partition = tp.partition();
+      log.info("{} - removing partition: {}", id, partition);
+      Map<String, Long> removed = handler.removePartition(partition);
+      for (String key : removed.keySet())
+      {
+        log.info(
+            "{} - Seen {} messages for partition={}|key={}",
+            id,
+            removed.get(key),
+            partition,
+            key);
+      }
+    });
+  }
+}