src/main/java/net/pterodactylus/sone/database/memory/MemoryFriendDatabase.java

   1 package net.pterodactylus.sone.database.memory;
   2
   3 import java.util.Collection;
   4 import java.util.concurrent.locks.ReadWriteLock;
   5 import java.util.concurrent.locks.ReentrantReadWriteLock;
   6
   7 import javax.annotation.Nonnull;
   8 import javax.annotation.Nullable;
   9
  10 import com.google.common.collect.HashMultimap;
  11 import com.google.common.collect.Multimap;
  12
  13 /**
  14  * In-memory implementation of friend-related functionality.
  15  *
  16  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  17  */
  18 class MemoryFriendDatabase {
  19
  20         private final ReadWriteLock lock = new ReentrantReadWriteLock();
  21         private final ConfigurationLoader configurationLoader;
  22         private final Multimap<String, String> soneFriends = HashMultimap.create();
  23
  24         MemoryFriendDatabase(ConfigurationLoader configurationLoader) {
  25                 this.configurationLoader = configurationLoader;
  26         }
  27
  28         Collection<String> getFriends(String localSoneId) {
  29                 loadFriends(localSoneId);
  30                 lock.readLock().lock();
  31                 try {
  32                         return soneFriends.get(localSoneId);
  33                 } finally {
  34                         lock.readLock().unlock();
  35                 }
  36         }
  37
  38         boolean isFriend(String localSoneId, String friendSoneId) {
  39                 loadFriends(localSoneId);
  40                 lock.readLock().lock();
  41                 try {
  42                         return soneFriends.containsEntry(localSoneId, friendSoneId);
  43                 } finally {
  44                         lock.readLock().unlock();
  45                 }
  46         }
  47
  48         void addFriend(String localSoneId, String friendSoneId) {
  49                 loadFriends(localSoneId);
  50                 lock.writeLock().lock();
  51                 try {
  52                         if (soneFriends.put(localSoneId, friendSoneId)) {
  53                                 configurationLoader.saveFriends(localSoneId, soneFriends.get(localSoneId));
  54                                 if (configurationLoader.getSoneFollowingTime(friendSoneId) == null) {
  55                                         configurationLoader.setSoneFollowingTime(friendSoneId, System.currentTimeMillis());
  56                                 }
  57                         }
  58                 } finally {
  59                         lock.writeLock().unlock();
  60                 }
  61         }
  62
  63         void removeFriend(String localSoneId, String friendSoneId) {
  64                 loadFriends(localSoneId);
  65                 lock.writeLock().lock();
  66                 try {
  67                         if (soneFriends.remove(localSoneId, friendSoneId)) {
  68                                 configurationLoader.saveFriends(localSoneId, soneFriends.get(localSoneId));
  69                                 boolean unfollowedSoneStillFollowed = false;
  70                                 for (String soneId : soneFriends.keys()) {
  71                                         unfollowedSoneStillFollowed |= getFriends(soneId).contains(friendSoneId);
  72                                 }
  73                                 if (!unfollowedSoneStillFollowed) {
  74                                         configurationLoader.removeSoneFollowingTime(friendSoneId);
  75                                 }
  76                         }
  77                 } finally {
  78                         lock.writeLock().unlock();
  79                 }
  80         }
  81
  82         @Nullable
  83         Long getFollowingTime(@Nonnull String soneId) {
  84                 return configurationLoader.getSoneFollowingTime(soneId);
  85         }
  86
  87         private void loadFriends(String localSoneId) {
  88                 lock.writeLock().lock();
  89                 try {
  90                         if (soneFriends.containsKey(localSoneId)) {
  91                                 return;
  92                         }
  93                         soneFriends.putAll(localSoneId, configurationLoader.loadFriends(localSoneId));
  94                 } finally {
  95                         lock.writeLock().unlock();
  96                 }
  97         }
  98
  99 }