juplo.de Git - demos/kafka/chat/blob - src/main/java/de/juplo/kafka/chat/backend/persistence/inmemory/InMemoryChatHomeService.java

   1 package de.juplo.kafka.chat.backend.persistence.inmemory;
   2
   3 import de.juplo.kafka.chat.backend.domain.*;
   4 import lombok.extern.slf4j.Slf4j;
   5 import reactor.core.publisher.Flux;
   6 import reactor.core.publisher.Mono;
   7
   8 import java.util.*;
   9
  10
  11 @Slf4j
  12 public class InMemoryChatHomeService implements ChatHomeService
  13 {
  14   private final Map<UUID, ChatRoom>[] chatrooms;
  15   private final Set<Integer> ownedShards;
  16   private final ShardingStrategy shardingStrategy;
  17
  18
  19   public InMemoryChatHomeService(
  20       int numShards,
  21       int[] ownedShards,
  22       ShardingStrategy shardingStrategy,
  23       Flux<ChatRoom> chatroomFlux)
  24   {
  25     log.debug("Creating InMemoryChatHomeService");
  26
  27     this.chatrooms = new Map[numShards];
  28
  29     this.ownedShards = Arrays
  30         .stream(ownedShards)
  31         .collect(
  32             () -> new HashSet<>(),
  33             (set, i) -> set.add(i),
  34             (a, b) -> a.addAll(b));
  35
  36     this.shardingStrategy = shardingStrategy;
  37
  38     for (int shard = 0; shard < numShards; shard++)
  39     {
  40       chatrooms[shard] = this.ownedShards.contains(shard)
  41           ? new HashMap<>()
  42           : null;
  43     }
  44     chatroomFlux
  45         .filter(chatRoom ->
  46         {
  47           if (this.ownedShards.contains(chatRoom.getShard()))
  48           {
  49             return true;
  50           }
  51           else
  52           {
  53             log.info("Ignoring not owned chat-room {}", chatRoom);
  54             return false;
  55           }
  56         })
  57         .toStream()
  58         .forEach(chatroom -> chatrooms[chatroom.getShard()].put(chatroom.getId(), chatroom));
  59   }
  60
  61   void putChatRoom(ChatRoom chatRoom)
  62   {
  63     UUID id = chatRoom.getId();
  64     int shard = shardingStrategy.selectShard(id);
  65     if (!ownedShards.contains(shard))
  66       throw new ShardNotOwnedException(this, chatRoom, shard, ownedShards);
  67     chatrooms[shard].put(id, chatRoom);
  68   }
  69
  70   @Override
  71   public Mono<ChatRoom> getChatRoom(UUID id)
  72   {
  73     int shard = shardingStrategy.selectShard(id);
  74     if (ownedShards.contains(shard))
  75     {
  76       return Mono.justOrEmpty(chatrooms[shard].get(id));
  77     }
  78     else
  79     {
  80       int[] ownedShards = new int[this.ownedShards.size()];
  81       Iterator<Integer> iterator = this.ownedShards.iterator();
  82       for (int i = 0; iterator.hasNext(); i++)
  83       {
  84         ownedShards[i] = iterator.next();
  85       }
  86       return Mono.error(new UnknownChatroomException(
  87           id,
  88           shard,
  89           ownedShards));
  90     }
  91   }
  92
  93   @Override
  94   public Flux<ChatRoom> getChatRooms()
  95   {
  96     return Flux
  97         .fromIterable(ownedShards)
  98         .flatMap(shard -> Flux.fromIterable(chatrooms[shard].values()));
  99   }
 100 }