refactor: Introduced `ConsumerTaskExecutor` -- Copied class

diff --git a/src/main/java/de/juplo/kafka/chat/backend/implementation/kafka/ConsumerTaskExecutor.java b/src/main/java/de/juplo/kafka/chat/backend/implementation/kafka/ConsumerTaskExecutor.java
new file mode 100644 (file)
index 0000000..b635dfc
--- /dev/null
+++ b/src/main/java/de/juplo/kafka/chat/backend/implementation/kafka/ConsumerTaskExecutor.java
@@ -0,0 +1,62 @@
+package de.juplo.kafka.chat.backend.implementation.kafka;
+
+import de.juplo.kafka.chat.backend.implementation.kafka.messages.AbstractMessageTo;
+import jakarta.annotation.PreDestroy;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.apache.kafka.clients.consumer.Consumer;
+import org.springframework.boot.ApplicationArguments;
+import org.springframework.boot.ApplicationRunner;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
+
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+
+
+@ConditionalOnProperty(
+    prefix = "chat.backend",
+    name = "services",
+    havingValue = "kafka")
+@RequiredArgsConstructor
+@Slf4j
+public class KafkaServicesApplicationRunner implements ApplicationRunner
+{
+  private final ThreadPoolTaskExecutor taskExecutor;
+  private final ChatRoomChannel chatRoomChannel;
+  private final Consumer<String, AbstractMessageTo> chatRoomChannelConsumer;
+  private final WorkAssignor workAssignor;
+
+  CompletableFuture<Void> chatRoomChannelConsumerJob;
+
+
+  @Override
+  public void run(ApplicationArguments args) throws Exception
+  {
+    workAssignor.assignWork(chatRoomChannelConsumer);
+    log.info("Starting the consumer for the ChatRoomChannel");
+    chatRoomChannelConsumerJob = taskExecutor
+        .submitCompletable(chatRoomChannel)
+        .exceptionally(e ->
+        {
+          log.error("The consumer for the ChatRoomChannel exited abnormally!", e);
+          return null;
+        });
+  }
+
+  @PreDestroy
+  public void joinChatRoomChannelConsumerJob()
+  {
+    log.info("Signaling the consumer of the CahtRoomChannel to quit its work");
+    chatRoomChannelConsumer.wakeup();
+    log.info("Waiting for the consumer of the ChatRoomChannel to finish its work");
+    chatRoomChannelConsumerJob.join();
+    log.info("Joined the consumer of the ChatRoomChannel");
+  }
+
+
+  interface WorkAssignor
+  {
+    void assignWork(Consumer<?, ?> consumer);
+  }
+}