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 import java.util.regex.Matcher;
  15 import java.util.regex.Pattern;
  16
  17
  18 @Slf4j
  19 @EqualsAndHashCode(of = { "id" })
  20 @ToString(of = { "id", "name" })
  21 public class ChatRoom
  22 {
  23   public final static Pattern VALID_USER = Pattern.compile("^[a-z0-9-]{2,}$");
  24   @Getter
  25   private final UUID id;
  26   @Getter
  27   private final String name;
  28   @Getter
  29   private final int shard;
  30   private final Clock clock;
  31   private final ChatRoomService service;
  32   private final int bufferSize;
  33   private Sinks.Many<Message> sink;
  34
  35
  36   public ChatRoom(
  37       UUID id,
  38       String name,
  39       int shard,
  40       Clock clock,
  41       ChatRoomService service,
  42       int bufferSize)
  43   {
  44     log.info("Created ChatRoom {} with buffer-size {}", id, bufferSize);
  45     this.id = id;
  46     this.name = name;
  47     this.shard = shard;
  48     this.clock = clock;
  49     this.service = service;
  50     this.bufferSize = bufferSize;
  51     // @RequiredArgsConstructor unfortunately not possible, because
  52     // the `bufferSize` is not set, if `createSink()` is called
  53     // from the variable declaration!
  54     this.sink = createSink();
  55   }
  56
  57
  58   synchronized public Mono<Message> addMessage(
  59       Long id,
  60       String user,
  61       String text)
  62   {
  63     Matcher matcher = VALID_USER.matcher(user);
  64     if (!matcher.matches())
  65       throw new InvalidUsernameException(user);
  66
  67     Message.MessageKey key = Message.MessageKey.of(user, id);
  68     return service
  69         .getMessage(key)
  70         .flatMap(existing -> text.equals(existing.getMessageText())
  71             ? Mono.just(existing)
  72             : Mono.error(() -> new MessageMutationException(existing, text)))
  73         .switchIfEmpty(
  74             Mono
  75                 .fromSupplier(() ->service.persistMessage(key, LocalDateTime.now(clock), text))
  76                 .doOnNext(m ->
  77                 {
  78                   Sinks.EmitResult result = sink.tryEmitNext(m);
  79                   if (result.isFailure())
  80                   {
  81                     log.warn("Emitting of message failed with {} for {}", result.name(), m);
  82                   }
  83                 }));
  84   }
  85
  86
  87   public Mono<Message> getMessage(String username, Long messageId)
  88   {
  89     Message.MessageKey key = Message.MessageKey.of(username, messageId);
  90     return service.getMessage(key);
  91   }
  92
  93   synchronized public Flux<Message> listen()
  94   {
  95     return sink
  96         .asFlux()
  97         .doOnCancel(() -> sink = createSink()); // Sink hast to be recreated on auto-cancel!
  98   }
  99
 100   public Flux<Message> getMessages()
 101   {
 102     return getMessages(0, Long.MAX_VALUE);
 103   }
 104
 105   public Flux<Message> getMessages(long first, long last)
 106   {
 107     return service.getMessages(first, last);
 108   }
 109
 110   private Sinks.Many<Message> createSink()
 111   {
 112     return Sinks
 113         .many()
 114         .multicast()
 115         .onBackpressureBuffer(bufferSize);
 116   }
 117 }