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 class MemoryFriendDatabase {
  17
  18         private final ReadWriteLock lock = new ReentrantReadWriteLock();
  19         private final ConfigurationLoader configurationLoader;
  20         private final Multimap<String, String> soneFriends = HashMultimap.create();
  21
  22         MemoryFriendDatabase(ConfigurationLoader configurationLoader) {
  23                 this.configurationLoader = configurationLoader;
  24         }
  25
  26         Collection<String> getFriends(String localSoneId) {
  27                 loadFriends(localSoneId);
  28                 lock.readLock().lock();
  29                 try {
  30                         return soneFriends.get(localSoneId);
  31                 } finally {
  32                         lock.readLock().unlock();
  33                 }
  34         }
  35
  36         boolean isFriend(String localSoneId, String friendSoneId) {
  37                 loadFriends(localSoneId);
  38                 lock.readLock().lock();
  39                 try {
  40                         return soneFriends.containsEntry(localSoneId, friendSoneId);
  41                 } finally {
  42                         lock.readLock().unlock();
  43                 }
  44         }
  45
  46         void addFriend(String localSoneId, String friendSoneId) {
  47                 loadFriends(localSoneId);
  48                 lock.writeLock().lock();
  49                 try {
  50                         if (soneFriends.put(localSoneId, friendSoneId)) {
  51                                 configurationLoader.saveFriends(localSoneId, soneFriends.get(localSoneId));
  52                                 if (configurationLoader.getSoneFollowingTime(friendSoneId) == null) {
  53                                         configurationLoader.setSoneFollowingTime(friendSoneId, System.currentTimeMillis());
  54                                 }
  55                         }
  56                 } finally {
  57                         lock.writeLock().unlock();
  58                 }
  59         }
  60
  61         void removeFriend(String localSoneId, String friendSoneId) {
  62                 loadFriends(localSoneId);
  63                 lock.writeLock().lock();
  64                 try {
  65                         if (soneFriends.remove(localSoneId, friendSoneId)) {
  66                                 configurationLoader.saveFriends(localSoneId, soneFriends.get(localSoneId));
  67                                 boolean unfollowedSoneStillFollowed = false;
  68                                 for (String soneId : soneFriends.keys()) {
  69                                         unfollowedSoneStillFollowed |= getFriends(soneId).contains(friendSoneId);
  70                                 }
  71                                 if (!unfollowedSoneStillFollowed) {
  72                                         configurationLoader.removeSoneFollowingTime(friendSoneId);
  73                                 }
  74                         }
  75                 } finally {
  76                         lock.writeLock().unlock();
  77                 }
  78         }
  79
  80         @Nullable
  81         Long getFollowingTime(@Nonnull String soneId) {
  82                 return configurationLoader.getSoneFollowingTime(soneId);
  83         }
  84
  85         private void loadFriends(String localSoneId) {
  86                 lock.writeLock().lock();
  87                 try {
  88                         if (soneFriends.containsKey(localSoneId)) {
  89                                 return;
  90                         }
  91                         soneFriends.putAll(localSoneId, configurationLoader.loadFriends(localSoneId));
  92                 } finally {
  93                         lock.writeLock().unlock();
  94                 }
  95         }
  96
  97 }