Changed how we deal with CB world reference. Partially fixes #923.

src/main/java/com/onarandombox/MultiverseCore/MVWorld.java

@@ -42,8 +42,6 @@ import org.bukkit.permissions.PermissionDefault;
 import org.bukkit.util.Vector;
 import org.json.simple.JSONObject;
 
-import java.lang.ref.Reference;
-import java.lang.ref.WeakReference;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -92,7 +90,6 @@ public class MVWorld extends SerializationConfig implements MultiverseWorld {
 
     private MultiverseCore plugin; // Hold the Plugin Instance.
 
-    private volatile Reference<World> world = new WeakReference<World>(null); // A reference to the World Instance.
     private String name; // The Worlds Name, EG its folder name.
 
     /**
@@ -212,8 +209,11 @@ public class MVWorld extends SerializationConfig implements MultiverseWorld {
         public Boolean validateChange(String property, Boolean newValue, Boolean oldValue,
                 MVWorld object) throws ChangeDeniedException {
             if (!newValue) {
-                world.get().setStorm(false);
+                final World world = getCBWorld();
-                world.get().setThundering(false);
+                if (world != null) {
+                    world.setStorm(false);
+                    world.setThundering(false);
+                }
             }
             return super.validateChange(property, newValue, oldValue, object);
         }
@@ -237,13 +237,16 @@ public class MVWorld extends SerializationConfig implements MultiverseWorld {
             } else {
                 allowMonsters = true;
             }
-            if (MVWorld.this.spawning.getAnimalSettings().getSpawnRate() != -1) {
+            final World world = getCBWorld();
-                world.get().setTicksPerAnimalSpawns(MVWorld.this.spawning.getAnimalSettings().getSpawnRate());
+            if (world != null) {
+                if (MVWorld.this.spawning.getAnimalSettings().getSpawnRate() != -1) {
+                    world.setTicksPerAnimalSpawns(MVWorld.this.spawning.getAnimalSettings().getSpawnRate());
+                }
+                if (MVWorld.this.spawning.getMonsterSettings().getSpawnRate() != -1) {
+                    world.setTicksPerMonsterSpawns(MVWorld.this.spawning.getMonsterSettings().getSpawnRate());
+                }
+                world.setSpawnFlags(allowMonsters, allowAnimals);
             }
-            if (MVWorld.this.spawning.getMonsterSettings().getSpawnRate() != -1) {
-                world.get().setTicksPerMonsterSpawns(MVWorld.this.spawning.getMonsterSettings().getSpawnRate());
-            }
-            world.get().setSpawnFlags(allowMonsters, allowAnimals);
             plugin.getMVWorldManager().getTheWorldPurger().purgeWorld(MVWorld.this);
             return super.validateChange(property, newValue, oldValue, object);
         }
@@ -375,12 +378,16 @@ public class MVWorld extends SerializationConfig implements MultiverseWorld {
     private volatile VirtualProperty<Boolean> pvp = new VirtualProperty<Boolean>() {
         @Override
         public void set(Boolean newValue) {
-            world.get().setPVP(newValue);
+            final World world = getCBWorld();
+            if (world != null) {
+                world.setPVP(newValue);
+            }
         }
 
         @Override
         public Boolean get() {
-            return world.get().getPVP();
+            final World world = getCBWorld();
+            return world != null ? world.getPVP() : null;
         }
     };
     @Property(validator = ScalePropertyValidator.class, description = "Scale must be a positive double value. ex: 2.3")
@@ -394,12 +401,16 @@ public class MVWorld extends SerializationConfig implements MultiverseWorld {
     private volatile VirtualProperty<Difficulty> difficulty = new VirtualProperty<Difficulty>() {
         @Override
         public void set(Difficulty newValue) {
-            world.get().setDifficulty(newValue);
+            final World world = getCBWorld();
+            if (world != null) {
+                world.setDifficulty(newValue);
+            }
         }
 
         @Override
         public Difficulty get() {
-            return world.get().getDifficulty();
+            final World world = getCBWorld();
+            return world != null ? world.getDifficulty() : null;
         }
     };
     @Property(validator = SpawningPropertyValidator.class, description = "Sorry, 'animals' must either be: true or false.")
@@ -421,12 +432,16 @@ public class MVWorld extends SerializationConfig implements MultiverseWorld {
     private volatile VirtualProperty<Boolean> keepSpawnInMemory = new VirtualProperty<Boolean>() {
         @Override
         public void set(Boolean newValue) {
-            world.get().setKeepSpawnInMemory(newValue);
+            final World world = getCBWorld();
+            if (world != null) {
+                world.setKeepSpawnInMemory(newValue);
+            }
         }
 
         @Override
         public Boolean get() {
-            return world.get().getKeepSpawnInMemory();
+            final World world = getCBWorld();
+            return world != null ? world.getKeepSpawnInMemory() : null;
         }
     };
     @Property
@@ -461,12 +476,16 @@ public class MVWorld extends SerializationConfig implements MultiverseWorld {
     private volatile VirtualProperty<Long> time = new VirtualProperty<Long>() {
         @Override
         public void set(Long newValue) {
-            world.get().setTime(newValue);
+            final World world = getCBWorld();
+            if (world != null) {
+                world.setTime(newValue);
+            }
         }
 
         @Override
         public Long get() {
-            return world.get().getTime();
+            final World world = getCBWorld();
+            return world != null ? world.getTime() : null;
         }
     };
     @Property
@@ -554,8 +573,6 @@ public class MVWorld extends SerializationConfig implements MultiverseWorld {
     public void init(World cbWorld, MultiverseCore thePlugin) {
         this.plugin = thePlugin;
 
-        // Weak reference so the CB-World can be unloaded even if this object still exists!
-        this.world = new WeakReference<World>(cbWorld);
         this.environment = cbWorld.getEnvironment();
         this.seed = cbWorld.getSeed();
         this.name = cbWorld.getName();
@@ -670,7 +687,7 @@ public class MVWorld extends SerializationConfig implements MultiverseWorld {
         this.adjustSpawn = true;
         this.portalForm = AllowedPortalType.ALL;
         this.gameMode = GameMode.SURVIVAL;
-        this.spawnLocation = (world != null) ? new SpawnLocation(world.get().getSpawnLocation()) : new NullLocation();
+        this.spawnLocation = (getCBWorld() != null) ? new SpawnLocation(getCBWorld().getSpawnLocation()) : new NullLocation();
         this.autoLoad = true;
         this.bedRespawn = true;
         this.worldBlacklist = new ArrayList<String>();
@@ -725,7 +742,14 @@ public class MVWorld extends SerializationConfig implements MultiverseWorld {
      */
     @Override
     public World getCBWorld() {
-        return this.world.get();
+        if (name == null) {
+            return null;
+        }
+        final World world = plugin.getServer().getWorld(name);
+        if (world == null) {
+            Logging.severe("Lost reference to bukkit world '%s'", name);
+        }
+        return world;
     }
 
     /**
@@ -884,7 +908,8 @@ public class MVWorld extends SerializationConfig implements MultiverseWorld {
     @Override
     public WorldType getWorldType() {
         // This variable is not settable in-game, therefore does not get a property.
-        return world.get().getWorldType();
+        final World world = getCBWorld();
+        return world != null ? world.getWorldType() : null;
     }
 
     /**

src/main/java/com/onarandombox/MultiverseCore/MultiverseCore.java

@@ -82,6 +82,8 @@ import com.onarandombox.MultiverseCore.utils.WorldManager;
 import com.pneumaticraft.commandhandler.CommandHandler;
 import me.main__.util.SerializationConfig.SerializationConfig;
 import org.bukkit.ChatColor;
+import org.bukkit.Difficulty;
+import org.bukkit.GameMode;
 import org.bukkit.Location;
 import org.bukkit.World.Environment;
 import org.bukkit.command.Command;
@@ -641,10 +643,9 @@ public class MultiverseCore extends JavaPlugin implements MVPlugin, Core {
 
                 // migrate gamemode
                 if (section.isString("gamemode")) {
-                    try {
+                    final GameMode gameMode = GameMode.valueOf(section.getString("gamemode").toUpperCase());
-                        world.setPropertyValue("gamemode", section.getString("gamemode"));
+                    if (gameMode != null) {
-                    } catch (PropertyDoesNotExistException e) {
+                        world.setGameMode(gameMode);
-                        throw new RuntimeException("Who forgot to update the migrator?", e);
                     }
                 }
 
@@ -729,6 +730,19 @@ public class MultiverseCore extends JavaPlugin implements MVPlugin, Core {
                     world.setSpawnLocation(spawnLoc);
                 }
 
+                // migrate difficulty
+                if (section.isString("difficulty")) {
+                    final Difficulty difficulty = Difficulty.valueOf(section.getString("difficulty").toUpperCase());
+                    if (difficulty != null) {
+                        world.setDifficulty(difficulty);
+                    }
+                }
+
+                // migrate keepspawninmemory
+                if (section.isBoolean("keepspawninmemory")) {
+                    world.setKeepSpawnInMemory(section.getBoolean("keepspawninmemory"));
+                }
+
                 newValues.put(entry.getKey(), world);
                 wasChanged = true;
             } else {

src/test/java/com/onarandombox/MultiverseCore/test/TestWorldProperties.java

@@ -20,6 +20,7 @@ import org.bukkit.ChatColor;
 import org.bukkit.Difficulty;
 import org.bukkit.GameMode;
 import org.bukkit.Location;
+import org.bukkit.World;
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandSender;
 import org.bukkit.configuration.file.FileConfiguration;
@@ -332,17 +333,18 @@ public class TestWorldProperties {
     }
 
     public void createEvents(MultiverseWorld mvWorld) {
+        final World world = mvWorld.getCBWorld();
         //// Weather events
         // weather change
-        weatherChangeOffEvent = new WeatherChangeEvent(mvWorld.getCBWorld(), false);
+        weatherChangeOffEvent = new WeatherChangeEvent(world, false);
-        weatherChangeOnEvent = new WeatherChangeEvent(mvWorld.getCBWorld(), true);
+        weatherChangeOnEvent = new WeatherChangeEvent(world, true);
         // thunder change
-        thunderChangeOffEvent = new ThunderChangeEvent(mvWorld.getCBWorld(), false);
+        thunderChangeOffEvent = new ThunderChangeEvent(world, false);
-        thunderChangeOnEvent = new ThunderChangeEvent(mvWorld.getCBWorld(), true);
+        thunderChangeOnEvent = new ThunderChangeEvent(world, true);
         //// Player events
         // player chat
         mockPlayer = mock(Player.class);
-        when(mockPlayer.getWorld()).thenReturn(mvWorld.getCBWorld());
+        when(mockPlayer.getWorld()).thenReturn(world);
         when(mockPlayer.hasPlayedBefore()).thenReturn(true);
         when(mockPlayer.hasPermission("multiverse.access.world")).thenReturn(true);
         when(mockPlayer.getName()).thenReturn("MultiverseMan");
@@ -368,7 +370,7 @@ public class TestWorldProperties {
         // entity regain health
         entityRegainHealthEvent = PowerMockito.mock(EntityRegainHealthEvent.class);
         when(entityRegainHealthEvent.getRegainReason()).thenReturn(RegainReason.REGEN);
-        when(mockHumanEntity.getLocation()).thenReturn(new Location(mvWorld.getCBWorld(), 0, 0, 0));
+        when(mockHumanEntity.getLocation()).thenReturn(new Location(world, 0, 0, 0));
         when(entityRegainHealthEvent.getEntity()).thenReturn(mockHumanEntity);
         // entity food level change event
         entityFoodLevelChangeEvent = PowerMockito.mock(FoodLevelChangeEvent.class);