refactor: One stream -> using `flatMap` instead of an inner `subscribe`
[demos/kafka/chat] / src / main / java / de / juplo / kafka / chat / backend / implementation / StorageStrategy.java
1 package de.juplo.kafka.chat.backend.implementation;
2
3 import de.juplo.kafka.chat.backend.domain.ChatHomeService;
4 import de.juplo.kafka.chat.backend.domain.ChatRoomInfo;
5 import de.juplo.kafka.chat.backend.domain.Message;
6 import org.slf4j.Logger;
7 import org.slf4j.LoggerFactory;
8 import reactor.core.publisher.Flux;
9 import reactor.core.publisher.Mono;
10
11 import java.util.UUID;
12
13
14 public interface StorageStrategy
15 {
16   Logger log = LoggerFactory.getLogger(StorageStrategy.class.getCanonicalName());
17
18   default Flux<ChatRoomInfo> write(ChatHomeService chatHomeService)
19   {
20     return writeChatRoomInfo(
21         chatHomeService
22             .getChatRoomInfo()
23             .flatMap(chatRoomInfo -> writeChatRoomData(
24                 chatRoomInfo.getId(),
25                 chatHomeService
26                     .getChatRoomData(chatRoomInfo.getId())
27                     .flatMapMany(chatRoomData -> chatRoomData.getMessages())
28                 )
29                 .then(Mono.just(chatRoomInfo))
30                 .doOnSuccess(emittedChatRoomInfo -> log.info("Stored {}", chatRoomInfo))
31                 .doOnError(throwable -> log.error("Could not store {}: {}", chatRoomInfo, throwable)))
32         )
33         .doOnComplete(() -> log.info("Stored {}", chatHomeService))
34         .doOnError(throwable -> log.error("Could not store {}: {}", chatHomeService, throwable));
35   }
36
37   Flux<ChatRoomInfo> writeChatRoomInfo(Flux<ChatRoomInfo> chatRoomInfoFlux);
38   Flux<ChatRoomInfo> readChatRoomInfo();
39   Flux<Message> writeChatRoomData(UUID chatRoomId, Flux<Message> messageFlux);
40   Flux<Message> readChatRoomData(UUID chatRoomId);
41 }