Fix loading multiple worlds at once

core/src/main/java/de/erethon/dungeonsxl/DungeonsXL.java

@@ -60,6 +60,7 @@ import java.util.List;
 import java.util.Set;
 import java.util.concurrent.CopyOnWriteArrayList;
 import org.bukkit.Bukkit;
+import org.bukkit.ChatColor;
 import org.bukkit.event.HandlerList;
 import org.bukkit.inventory.Inventory;
 
@@ -88,6 +89,8 @@ public class DungeonsXL extends DREPlugin {
     public static File MOBS;
     public static File SIGNS;
 
+    private boolean loadingWorld;
+
     private GlobalData globalData;
     private MainConfig mainConfig;
 
@@ -287,6 +290,26 @@ public class DungeonsXL extends DREPlugin {
         }
     }
 
+    /**
+     * Returns true if the plugin is currently loading a world, false if not.<p>
+     * If the plugin is loading a world, it is locked in order to prevent loading two at once.
+     *
+     * @return true if the plugin is currently loading a world, false if not
+     */
+    public boolean isLoadingWorld() {
+        return loadingWorld;
+    }
+
+    /**
+     * Notifies the plugin that a world is being loaded.<p>
+     * If the plugin is loading a world, it is locked in order to prevent loading two at once.
+     *
+     * @param loadingWorld if a world is being loaded
+     */
+    public void setLoadingWorld(boolean loadingWorld) {
+        this.loadingWorld = loadingWorld;
+    }
+
     /**
      * @return the loaded instance of GlobalData
      */

core/src/main/java/de/erethon/dungeonsxl/global/DPortal.java

@@ -205,8 +205,11 @@ public class DPortal extends GlobalProtection {
      * @param player the player to teleport into his dungeon
      */
     public void teleport(Player player) {
-        DGroup dGroup = DGroup.getByPlayer(player);
+        if (plugin.isLoadingWorld()) {
+            return;
+        }
 
+        DGroup dGroup = DGroup.getByPlayer(player);
         if (dGroup == null) {
             MessageUtil.sendMessage(player, DMessage.ERROR_JOIN_GROUP.getMessage());
             return;

core/src/main/java/de/erethon/dungeonsxl/world/DResourceWorld.java

@@ -198,6 +198,7 @@ public class DResourceWorld {
      * @return an instance of this world
      */
     public DInstanceWorld instantiate(boolean game) {
+        plugin.setLoadingWorld(true);
         int id = worlds.generateId();
         String name = worlds.generateName(game, id);
 
@@ -235,6 +236,7 @@ public class DResourceWorld {
             signData.deserializeSigns((DEditWorld) instance);
         }
 
+        plugin.setLoadingWorld(false);
         return instance;
     }
 
@@ -243,6 +245,9 @@ public class DResourceWorld {
      * @return an old or a new instance of this world.
      */
     public DEditWorld instantiateAsEditWorld(boolean ignoreLimit) {
+        if (plugin.isLoadingWorld()) {
+            return null;
+        }
         if (!ignoreLimit && plugin.getMainConfig().getMaxInstances() <= worlds.getInstances().size()) {
             return null;
         }
@@ -262,6 +267,9 @@ public class DResourceWorld {
      * @return a new instance of this world
      */
     public DGameWorld instantiateAsGameWorld(boolean ignoreLimit) {
+        if (plugin.isLoadingWorld()) {
+            return null;
+        }
         if (!ignoreLimit && plugin.getMainConfig().getMaxInstances() <= worlds.getInstances().size()) {
             return null;
         }