Query server's player cache for missing players

This uses a cache for players that we haven't found before so to not check the cache too often and also checks if the online mode of the queried OfflinePlayer matches the server's mode (gotten from the first logged-in player in order to be compatible with BungeeCord requiring the server to be in offline-mode.

src/main/java/com/Acrobot/Breeze/Collection/SimpleCache.java

@@ -40,7 +40,7 @@ public class SimpleCache<K, V> {
         }
     }
 
-    private boolean contains(K key) {
+    public boolean contains(K key) {
         return map.containsKey(key);
     }
 }

src/main/java/com/Acrobot/ChestShop/Listeners/Player/PlayerConnect.java

@@ -17,6 +17,10 @@ public class PlayerConnect implements Listener {
 
     @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
     public static void onPlayerConnect(final PlayerJoinEvent event) {
+        if (NameManager.getUuidVersion() < 0) {
+            NameManager.setUuidVersion(event.getPlayer().getUniqueId().version());
+        }
+
         final PlayerDTO playerDTO = new PlayerDTO(event.getPlayer());
 
         Bukkit.getScheduler().runTaskAsynchronously(ChestShop.getPlugin(), new Runnable() {

src/main/java/com/Acrobot/ChestShop/UUIDs/NameManager.java

@@ -34,9 +34,11 @@ public class NameManager {
     private static SimpleCache<String, Account> usernameToAccount = new SimpleCache<>(Properties.CACHE_SIZE);
     private static SimpleCache<UUID, Account> uuidToAccount = new SimpleCache<>(Properties.CACHE_SIZE);
     private static SimpleCache<String, Account> shortToAccount = new SimpleCache<>(Properties.CACHE_SIZE);
+    private static SimpleCache<String, Boolean> invalidPlayers = new SimpleCache<>(Properties.CACHE_SIZE);
 
     private static Account adminAccount;
     private static Account serverEconomyAccount;
+    private static int uuidVersion = -1;
 
     /**
      * Get account info from a UUID
@@ -102,26 +104,38 @@ public class NameManager {
      */
     public static Account getAccountFromShortName(String shortName) {
         Validate.notEmpty(shortName, "shortName cannot be null or empty!");
+        Account account = null;
+
         if (shortName.length() > 15) {
-            return getAccount(shortName);
+            account = getAccount(shortName);
+        } else {
+            try {
+                account = shortToAccount.get(shortName, () -> {
+                    try {
+                        Account a = accounts.queryBuilder().where().eq("shortName", shortName).queryForFirst();
+                        if (a != null) {
+                            a.setShortName(shortName); // HOW IS IT EVEN POSSIBLE THAT THE NAME IS NOT SET EVEN IF WE HAVE FOUND THE PLAYER?!
+                            return a;
+                        }
+                    } catch (SQLException e) {
+                        ChestShop.getBukkitLogger().log(Level.WARNING, "Error while getting account for " + shortName + ":", e);
+                    }
+                    throw new Exception("Could not find account for " + shortName);
+                });
+            } catch (ExecutionException ignored) {}
         }
 
-        try {
-            return shortToAccount.get(shortName, () -> {
-                try {
-                    Account account = accounts.queryBuilder().where().eq("shortName", shortName).queryForFirst();
-                    if (account != null) {
-                        account.setShortName(shortName); // HOW IS IT EVEN POSSIBLE THAT THE NAME IS NOT SET EVEN IF WE HAVE FOUND THE PLAYER?!
-                        return account;
-                    }
-                } catch (SQLException e) {
-                    ChestShop.getBukkitLogger().log(Level.WARNING, "Error while getting account for " + shortName + ":", e);
-                }
-                throw new Exception("Could not find account for " + shortName);
-            });
-        } catch (ExecutionException ignored) {
-            return null;
+        if (account == null && !invalidPlayers.contains(shortName.toLowerCase())) {
+            // no account with that shortname was found, try to get an offline player with that name
+            OfflinePlayer offlinePlayer = ChestShop.getBukkitServer().getOfflinePlayer(shortName);
+            if (offlinePlayer != null && offlinePlayer.getName() != null && offlinePlayer.getUniqueId() != null
+                    && offlinePlayer.getUniqueId().version() == uuidVersion) {
+                account = storeUsername(new PlayerDTO(offlinePlayer.getUniqueId(), offlinePlayer.getName()));
+            } else {
+                invalidPlayers.put(shortName.toLowerCase(), true);
+            }
         }
+        return account;
     }
 
     /**
@@ -222,8 +236,9 @@ public class NameManager {
      * Store the username of a player into the database and the username-uuid cache
      *
      * @param player The data transfer object of the player to store
+     * @return The stored/updated account. <tt>null</tt> if there was an error updating it
      */
-    public static void storeUsername(final PlayerDTO player) {
+    public static Account storeUsername(final PlayerDTO player) {
         final UUID uuid = player.getUniqueId();
 
         Account latestAccount = null;
@@ -243,11 +258,14 @@ public class NameManager {
             accounts.createOrUpdate(latestAccount);
         } catch (SQLException e) {
             ChestShop.getBukkitLogger().log(Level.WARNING, "Error while updating account " + latestAccount + ":", e);
+            return null;
         }
 
         usernameToAccount.put(latestAccount.getName(), latestAccount);
         uuidToAccount.put(uuid, latestAccount);
         shortToAccount.put(latestAccount.getShortName(), latestAccount);
+
+        return latestAccount;
     }
 
     /**
@@ -317,4 +335,11 @@ public class NameManager {
         return serverEconomyAccount;
     }
 
+    public static void setUuidVersion(int uuidVersion) {
+        NameManager.uuidVersion = uuidVersion;
+    }
+
+    public static int getUuidVersion() {
+        return uuidVersion;
+    }
 }