refactor: One stream -> using `flatMap` instead of an inner `subscribe`

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

diff --git a/src/main/java/de/juplo/kafka/chat/backend/implementation/StorageStrategy.java b/src/main/java/de/juplo/kafka/chat/backend/implementation/StorageStrategy.java
index 019db65..f9ce2b1 100644 (file)
--- a/src/main/java/de/juplo/kafka/chat/backend/implementation/StorageStrategy.java
+++ b/src/main/java/de/juplo/kafka/chat/backend/implementation/StorageStrategy.java
@@ -6,84 +6,36 @@ import de.juplo.kafka.chat.backend.domain.Message;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
 
 import java.util.UUID;
-import java.util.function.BiConsumer;
-import java.util.function.Consumer;
 
 
 public interface StorageStrategy
 {
   Logger log = LoggerFactory.getLogger(StorageStrategy.class.getCanonicalName());
 
-  default void write(ChatHomeService chatHomeService)
+  default Flux<ChatRoomInfo> write(ChatHomeService chatHomeService)
   {
-    write(
-        chatHomeService,
-        this::logSuccessChatHomeService,
-        this::logFailureChatHomeService);
-  }
-
-  default void write(
-      ChatHomeService chatHomeService,
-      ChatHomeServiceWrittenSuccessCallback successCallback,
-      ChatHomeServiceWrittenFailureCallback failureCallback)
-  {
-    writeChatRoomInfo(
+    return writeChatRoomInfo(
         chatHomeService
             .getChatRoomInfo()
-            .doOnComplete(() -> successCallback.accept(chatHomeService))
-            .doOnError(throwable -> failureCallback.accept(chatHomeService, throwable))
-            .doOnNext(chatRoomInfo ->
+            .flatMap(chatRoomInfo ->
                 writeChatRoomData(
                     chatRoomInfo.getId(),
                     chatHomeService
                         .getChatRoomData(chatRoomInfo.getId())
-                        .flatMapMany(chatRoomData -> chatRoomData.getMessages()),
-                    this::logSuccessChatRoom,
-                    this::logFailureChatRoom)));
+                        .flatMapMany(chatRoomData -> chatRoomData.getMessages())
+                        )
+                    .then(Mono.just(chatRoomInfo))
+                    .doOnSuccess(empty -> log.info("Stored {}", chatRoomInfo))
+                    .doOnError(throwable -> log.error("Could not store {}: {}", chatRoomInfo, throwable))))
+        .doOnComplete(() -> log.info("Stored {}", chatHomeService))
+        .doOnError(throwable -> log.error("Could not store {}: {}", chatHomeService, throwable));
   }
 
-  void writeChatRoomInfo(Flux<ChatRoomInfo> chatRoomInfoFlux);
+  Flux<ChatRoomInfo> writeChatRoomInfo(Flux<ChatRoomInfo> chatRoomInfoFlux);
   Flux<ChatRoomInfo> readChatRoomInfo();
-  default void writeChatRoomData(
-      UUID chatRoomId,
-      Flux<Message> messageFlux,
-      ChatRoomWrittenSuccessCallback successCallback,
-      ChatRoomWrittenFailureCallback failureCallback)
-  {
-    writeChatRoomData(
-        chatRoomId,
-        messageFlux
-            .doOnComplete(() -> successCallback.accept(chatRoomId))
-            .doOnError(throwable -> failureCallback.accept(chatRoomId, throwable)));
-  }
-  void writeChatRoomData(UUID chatRoomId, Flux<Message> messageFlux);
+  Flux<Message> writeChatRoomData(UUID chatRoomId, Flux<Message> messageFlux);
   Flux<Message> readChatRoomData(UUID chatRoomId);
-
-  interface ChatHomeServiceWrittenSuccessCallback extends Consumer<ChatHomeService> {}
-  interface ChatHomeServiceWrittenFailureCallback extends BiConsumer<ChatHomeService, Throwable> {}
-
-  default void logSuccessChatHomeService(ChatHomeService chatHomeService)
-  {
-    log.info("Successfully stored {}", chatHomeService);
-  }
-
-  default void logFailureChatHomeService(ChatHomeService chatHomeService, Throwable throwable)
-  {
-    log.error("Could not store {}: {}", chatHomeService, throwable);
-  }
-
-  interface ChatRoomWrittenSuccessCallback extends Consumer<UUID> {}
-  interface ChatRoomWrittenFailureCallback extends BiConsumer<UUID, Throwable> {}
-
-  default void logSuccessChatRoom(UUID chatRoomId)
-  {
-    log.info("Successfully stored chat-room {}", chatRoomId);
-  }
-
-  default void logFailureChatRoom(UUID chatRoomId, Throwable throwable)
-  {
-    log.error("Could not store chat-room {}: {}", chatRoomId, throwable);
-  }
 }