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

   1 package de.juplo.kafka.chat.backend.persistence.inmemory;
   2
   3 import de.juplo.kafka.chat.backend.domain.*;
   4 import de.juplo.kafka.chat.backend.persistence.ShardingStrategy;
   5 import lombok.extern.slf4j.Slf4j;
   6 import reactor.core.publisher.Flux;
   7 import reactor.core.publisher.Mono;
   8
   9 import java.util.HashSet;
  10 import java.util.Set;
  11 import java.util.UUID;
  12 import java.util.stream.Collectors;
  13
  14
  15 @Slf4j
  16 public class ShardedChatHome implements ChatHome
  17 {
  18   private final SimpleChatHome[] chatHomes;
  19   private final Set<Integer> ownedShards;
  20   private final ShardingStrategy shardingStrategy;
  21
  22
  23   public  ShardedChatHome(
  24       SimpleChatHome[] chatHomes,
  25       ShardingStrategy shardingStrategy)
  26   {
  27     this.chatHomes = chatHomes;
  28     this.shardingStrategy = shardingStrategy;
  29     this.ownedShards = new HashSet<>();
  30     for (int shard = 0; shard < chatHomes.length; shard++)
  31       if(chatHomes[shard] != null)
  32         this.ownedShards.add(shard);
  33     log.info(
  34         "Created ShardedChatHome for shards: {}",
  35         ownedShards
  36             .stream()
  37             .map(String::valueOf)
  38             .collect(Collectors.joining(", ")));
  39   }
  40
  41
  42   @Override
  43   public Mono<ChatRoomInfo> createChatRoom(UUID id, String name)
  44   {
  45     int shard = shardingStrategy.selectShard(id);
  46     return chatHomes[shard] == null
  47         ? Mono.error(new ShardNotOwnedException(shard))
  48         : chatHomes[shard].createChatRoom(id, name);
  49   }
  50
  51   @Override
  52   public Mono<ChatRoomInfo> getChatRoomInfo(UUID id)
  53   {
  54     int shard = selectShard(id);
  55     return chatHomes[shard] == null
  56         ? Mono.error(new ShardNotOwnedException(shard))
  57         : chatHomes[shard]
  58             .getChatRoomInfo(id)
  59             .onErrorMap(throwable -> throwable instanceof UnknownChatroomException
  60             ? new UnknownChatroomException(
  61                 id,
  62                 shard,
  63                 ownedShards.stream().mapToInt(i -> i.intValue()).toArray())
  64             : throwable);
  65   }
  66
  67   @Override
  68   public Flux<ChatRoomInfo> getChatRoomInfo()
  69   {
  70     return Flux
  71         .fromIterable(ownedShards)
  72         .flatMap(shard -> chatHomes[shard].getChatRoomInfo());
  73   }
  74
  75   @Override
  76   public Mono<ChatRoomData> getChatRoomData(UUID id)
  77   {
  78     int shard = selectShard(id);
  79     return chatHomes[shard] == null
  80         ? Mono.error(new ShardNotOwnedException(shard))
  81         : chatHomes[shard]
  82             .getChatRoomData(id)
  83             .onErrorMap(throwable -> throwable instanceof UnknownChatroomException
  84                 ? new UnknownChatroomException(
  85                 id,
  86                 shard,
  87                 ownedShards.stream().mapToInt(i -> i.intValue()).toArray())
  88                 : throwable);
  89   }
  90
  91   public Flux<ChatRoomData> getChatRoomData()
  92   {
  93     return Flux
  94         .fromIterable(ownedShards)
  95         .flatMap(shard -> chatHomes[shard].getChatRoomData());
  96   }
  97
  98
  99
 100   private int selectShard(UUID chatroomId)
 101   {
 102     return shardingStrategy.selectShard(chatroomId);
 103   }
 104 }