refactor: DRY for computation of new `ChatRoomData` instances

[demos/kafka/chat] / src / main / java / de / juplo / kafka / chat / backend / implementation / kafka / DataChannel.java

diff --git a/src/main/java/de/juplo/kafka/chat/backend/implementation/kafka/DataChannel.java b/src/main/java/de/juplo/kafka/chat/backend/implementation/kafka/DataChannel.java
index 4d5a141..da90663 100644 (file)
--- a/src/main/java/de/juplo/kafka/chat/backend/implementation/kafka/DataChannel.java
+++ b/src/main/java/de/juplo/kafka/chat/backend/implementation/kafka/DataChannel.java
@@ -19,6 +19,7 @@ import reactor.core.publisher.Mono;
 
 import java.time.*;
 import java.util.*;
+import java.util.function.Function;
 import java.util.stream.IntStream;
 
 
@@ -36,6 +37,7 @@ public class DataChannel implements Runnable, ConsumerRebalanceListener
   private final long[] currentOffset;
   private final long[] nextOffset;
   private final Map<UUID, ChatRoomData>[] chatRoomData;
+  private final InfoChannel infoChannel;
 
   private boolean running;
   @Getter
@@ -49,7 +51,8 @@ public class DataChannel implements Runnable, ConsumerRebalanceListener
     ZoneId zoneId,
     int numShards,
     int bufferSize,
-    Clock clock)
+    Clock clock,
+    InfoChannel infoChannel)
   {
     log.debug(
         "Creating DataChannel for topic {} with {} partitions",
@@ -68,10 +71,8 @@ public class DataChannel implements Runnable, ConsumerRebalanceListener
     this.chatRoomData = new Map[numShards];
     IntStream
         .range(0, numShards)
-        .forEach(shard ->
-        {
-          this.chatRoomData[shard] = new HashMap<>();
-        });
+        .forEach(shard -> this.chatRoomData[shard] = new HashMap<>());
+    this.infoChannel = infoChannel;
   }
 
 
@@ -244,14 +245,9 @@ public class DataChannel implements Runnable, ConsumerRebalanceListener
     Message.MessageKey key = Message.MessageKey.of(chatMessageTo.getUser(), chatMessageTo.getId());
     Message message = new Message(key, offset, timestamp, chatMessageTo.getText());
 
-    ChatRoomData chatRoomData = this.chatRoomData[partition].computeIfAbsent(
-        chatRoomId,
-        (id) ->
-        {
-          log.info("Creating ChatRoom {} with buffer-size {}", id, bufferSize);
-          KafkaChatMessageService service = new KafkaChatMessageService(this, id);
-          return new ChatRoomData(clock, service, bufferSize);
-        });
+    ChatRoomData chatRoomData = this
+        .chatRoomData[partition]
+        .computeIfAbsent(chatRoomId, this::computeChatRoomData);
     KafkaChatMessageService kafkaChatRoomService =
         (KafkaChatMessageService) chatRoomData.getChatRoomService();
 
@@ -296,6 +292,16 @@ public class DataChannel implements Runnable, ConsumerRebalanceListener
       return Mono.error(new ShardNotOwnedException(shard));
     }
 
-    return Mono.justOrEmpty(chatRoomData[shard].get(id));
+    return infoChannel
+        .getChatRoomInfo(id)
+        .map(chatRoomInfo ->
+            chatRoomData[shard].computeIfAbsent(id, this::computeChatRoomData));
+  }
+
+  private ChatRoomData computeChatRoomData(UUID chatRoomId)
+  {
+    log.info("Creating ChatRoom {} with buffer-size {}", chatRoomId, bufferSize);
+    KafkaChatMessageService service = new KafkaChatMessageService(this, chatRoomId);
+    return new ChatRoomData(clock, service, bufferSize);
   }
 }