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.Getter;
   4 import lombok.extern.slf4j.Slf4j;
   5 import reactor.core.publisher.Flux;
   6 import reactor.core.publisher.Mono;
   7 import reactor.core.publisher.Sinks;
   8
   9 import java.time.LocalDateTime;
  10 import java.util.*;
  11
  12
  13 @Slf4j
  14 public class Chatroom
  15 {
  16   @Getter
  17   private final UUID id;
  18   @Getter
  19   private final String name;
  20   private final PersistenceStrategy persistence;
  21   private final int bufferSize;
  22   private Sinks.Many<Message> sink;
  23
  24   public Chatroom(
  25       UUID id,
  26       String name,
  27       PersistenceStrategy persistence,
  28       int bufferSize)
  29   {
  30     this.id = id;
  31     this.name = name;
  32     this.persistence = persistence;
  33     this.bufferSize = bufferSize;
  34     this.sink = createSink();
  35   }
  36
  37
  38   synchronized public Mono<Message> addMessage(
  39       Long id,
  40       LocalDateTime timestamp,
  41       String user,
  42       String text)
  43   {
  44     return persistence
  45         .persistMessage(Message.MessageKey.of(user, id), timestamp, text)
  46         .doOnNext(message ->
  47         {
  48           Sinks.EmitResult result = sink.tryEmitNext(message);
  49           if (result.isFailure())
  50           {
  51             log.warn("Emitting of message failed with {} for {}", result.name(), message);
  52           }
  53         });
  54   }
  55
  56
  57   public Mono<Message> getMessage(String username, Long messageId)
  58   {
  59     return persistence.getMessage(Message.MessageKey.of(username, messageId));
  60   }
  61
  62   synchronized public Flux<Message> listen()
  63   {
  64     return sink
  65         .asFlux()
  66         .doOnCancel(() -> sink = createSink()); // Sink hast to be recreated on auto-cancel!
  67   }
  68
  69   public Flux<Message> getMessages()
  70   {
  71     return getMessages(0, Long.MAX_VALUE);
  72   }
  73
  74   public Flux<Message> getMessages(long first, long last)
  75   {
  76     return persistence.getMessages(first, last);
  77   }
  78
  79   private Sinks.Many<Message> createSink()
  80   {
  81     return Sinks
  82         .many()
  83         .multicast()
  84         .onBackpressureBuffer(bufferSize);
  85   }
  86 }