juplo.de Git - demos/kafka/chat/blob - src/main/java/de/juplo/kafka/chat/backend/domain/ChatRoom.java

   1 package de.juplo.kafka.chat.backend.domain;
   2
   3 import lombok.EqualsAndHashCode;
   4 import lombok.Getter;
   5 import lombok.ToString;
   6 import lombok.extern.slf4j.Slf4j;
   7 import reactor.core.publisher.Flux;
   8 import reactor.core.publisher.Mono;
   9 import reactor.core.publisher.Sinks;
  10
  11 import java.time.Clock;
  12 import java.time.LocalDateTime;
  13 import java.util.*;
  14
  15
  16 @Slf4j
  17 @EqualsAndHashCode(of = { "id" })
  18 @ToString(of = { "id", "name" })
  19 public class ChatRoom
  20 {
  21   @Getter
  22   private final UUID id;
  23   @Getter
  24   private final String name;
  25   private final Clock clock;
  26   private final ChatRoomService service;
  27   private final int bufferSize;
  28   private Sinks.Many<Message> sink;
  29
  30   public ChatRoom(
  31       UUID id,
  32       String name,
  33       Clock clock,
  34       ChatRoomService service,
  35       int bufferSize)
  36   {
  37     this.id = id;
  38     this.name = name;
  39     this.clock = clock;
  40     this.service = service;
  41     this.bufferSize = bufferSize;
  42     this.sink = createSink();
  43   }
  44
  45
  46   synchronized public Mono<Message> addMessage(
  47       Long id,
  48       String user,
  49       String text)
  50   {
  51     Message.MessageKey key = Message.MessageKey.of(user, id);
  52     return service
  53         .getMessage(key)
  54         .flatMap(existing -> text.equals(existing.getMessageText())
  55             ? Mono.just(existing)
  56             : Mono.error(() -> new MessageMutationException(existing, text)))
  57         .switchIfEmpty(
  58             Mono
  59                 .just(service.persistMessage(key, LocalDateTime.now(clock), text))
  60                 .doOnNext(m ->
  61                 {
  62                   Sinks.EmitResult result = sink.tryEmitNext(m);
  63                   if (result.isFailure())
  64                   {
  65                     log.warn("Emitting of message failed with {} for {}", result.name(), m);
  66                   }
  67                 }));
  68   }
  69
  70
  71   public Mono<Message> getMessage(String username, Long messageId)
  72   {
  73     Message.MessageKey key = Message.MessageKey.of(username, messageId);
  74     return service.getMessage(key);
  75   }
  76
  77   synchronized public Flux<Message> listen()
  78   {
  79     return sink
  80         .asFlux()
  81         .doOnCancel(() -> sink = createSink()); // Sink hast to be recreated on auto-cancel!
  82   }
  83
  84   public Flux<Message> getMessages()
  85   {
  86     return getMessages(0, Long.MAX_VALUE);
  87   }
  88
  89   public Flux<Message> getMessages(long first, long last)
  90   {
  91     return service.getMessages(first, last);
  92   }
  93
  94   private Sinks.Many<Message> createSink()
  95   {
  96     return Sinks
  97         .many()
  98         .multicast()
  99         .onBackpressureBuffer(bufferSize);
 100   }
 101 }