Implemented internal Chunk generators. Now multiverse can have its own custom chunk generators. Implemented the void generator (very useful). Added world type "VOID" in environments list. When create or import a world with type VOID the world will be added as a NORMAL world with "multiverse:void" generator

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

@@ -78,6 +78,7 @@ import com.onarandombox.MultiverseCore.destination.PlayerDestination;
 import com.onarandombox.MultiverseCore.destination.WorldDestination;
 import com.onarandombox.MultiverseCore.event.MVDebugModeEvent;
 import com.onarandombox.MultiverseCore.event.MVVersionEvent;
+import com.onarandombox.MultiverseCore.generators.InternalChunkGeneratorManager;
 import com.onarandombox.MultiverseCore.listeners.MVAsyncPlayerChatListener;
 import com.onarandombox.MultiverseCore.listeners.MVChatListener;
 import com.onarandombox.MultiverseCore.listeners.MVEntityListener;
@@ -281,6 +282,11 @@ public class MultiverseCore extends JavaPlugin implements MVPlugin, Core {
 
         this.messaging = new MVMessaging();
         this.economist = new MVEconomist(this);
+        //CustomGenerators start
+        // Initialize internal chunk generator manager
+        InternalChunkGeneratorManager.init();
+        //CustomGenerators end
+
         // Load the defaultWorldGenerators
         this.worldManager.getDefaultWorldGenerators();
 

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

@@ -90,6 +90,12 @@ public class CreateCommand extends MultiverseCommand {
             return;
         }
 
+        //CustomGenerators start
+        if(env.equalsIgnoreCase("VOID")) {
+            env = "NORMAL";
+            generator = "multiverse:void";
+        }
+        //CustomGenerators end
         Environment environment = EnvironmentCommand.getEnvFromString(env);
         if (environment == null) {
             sender.sendMessage(ChatColor.RED + "That is not a valid environment.");
@@ -100,7 +106,12 @@ public class CreateCommand extends MultiverseCommand {
         // If they didn't specify a type, default to NORMAL
         if (typeString == null) {
             typeString = "NORMAL";
+        //CustomGenerators start
+        } else if(typeString.equalsIgnoreCase("VOID")) {
+            typeString = "NORMAL";
+            generator = "multiverse:void";
         }
+        //CustomGenerators end
         WorldType type = EnvironmentCommand.getWorldTypeFromString(typeString);
         if (type == null) {
             sender.sendMessage(ChatColor.RED + "That is not a valid World Type.");
@@ -108,6 +119,7 @@ public class CreateCommand extends MultiverseCommand {
             return;
         }
         // Determine if the generator is valid. #918
+
         if (generator != null) {
             List<String> genarray = new ArrayList<String>(Arrays.asList(generator.split(":")));
             if (genarray.size() < 2) {

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

@@ -45,6 +45,9 @@ public class EnvironmentCommand extends MultiverseCommand {
         sender.sendMessage(ChatColor.GREEN + "NORMAL");
         sender.sendMessage(ChatColor.RED + "NETHER");
         sender.sendMessage(ChatColor.AQUA + "END");
+        //CustomGenerators start
+        sender.sendMessage(ChatColor.WHITE + "VOID");
+        //CustomGenerators end
     }
     /**
      * Shows all valid known world types to a {@link CommandSender}.

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

@@ -106,6 +106,12 @@ public class ImportCommand extends MultiverseCommand {
         }
 
         String env = args.get(1);
+        //CustomGenerators start
+        if(env.equalsIgnoreCase("VOID")){
+            env = "NORMAL";
+            generator = "multiverse:void";
+        }
+        //CustomGenerators end
         Environment environment = EnvironmentCommand.getEnvFromString(env);
         if (environment == null) {
             sender.sendMessage(ChatColor.RED + "That is not a valid environment.");
@@ -113,6 +119,7 @@ public class ImportCommand extends MultiverseCommand {
             return;
         }
 
+
         if (!worldFile.exists()) {
             sender.sendMessage(ChatColor.RED + "FAILED.");
             String worldList = this.getPotentialWorldStrings();

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

@@ -0,0 +1,43 @@
+package com.onarandombox.MultiverseCore.generators;
+
+import com.onarandombox.MultiverseCore.generators.impl.MultiverseVoidGenerator;
+import org.bukkit.generator.ChunkGenerator;
+
+import java.util.Map;
+
+//CustomGenerators start
+public class InternalChunkGeneratorManager {
+
+    private final Map<String, ChunkGenerator> generators;
+
+    private static InternalChunkGeneratorManager instance;
+
+    public static InternalChunkGeneratorManager get() {
+        if (instance == null) {
+            throw new IllegalStateException("InternalChunkGeneratorManager has not been initialized yet.");
+        }
+        return instance;
+    }
+
+    public static void init(){
+        new InternalChunkGeneratorManager();
+    }
+
+    public InternalChunkGeneratorManager() {
+        instance = this;
+        //register internal generators instances (singleton)
+        generators = Map.of(
+                "VOID", new MultiverseVoidGenerator()
+        );
+    }
+
+    public boolean exists(String generator){
+        return generators.containsKey(generator);
+    }
+
+    public ChunkGenerator getGenerator(String generator){
+        return generators.getOrDefault(generator.toUpperCase(), null);
+    }
+
+}
+//CustomGenerators end

src/main/java/com/onarandombox/MultiverseCore/generators/impl/MultiverseVoidGenerator.java

@@ -0,0 +1,22 @@
+package com.onarandombox.MultiverseCore.generators.impl;
+
+import org.bukkit.Location;
+import org.bukkit.World;
+import org.bukkit.generator.ChunkGenerator;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Random;
+
+public class MultiverseVoidGenerator extends ChunkGenerator {
+
+    @Override
+    public @NotNull ChunkData generateChunkData(@NotNull World world, @NotNull Random random, int x, int z, @NotNull ChunkGenerator.BiomeGrid biome) {
+        return createChunkData(world);
+    }
+
+    @Override
+    public @Nullable Location getFixedSpawnLocation(@NotNull World world, @NotNull Random random) {
+        return new Location(world,0, 64, 0);
+    }
+}

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

@@ -17,6 +17,7 @@ import com.onarandombox.MultiverseCore.api.MultiverseWorld;
 import com.onarandombox.MultiverseCore.api.SafeTTeleporter;
 import com.onarandombox.MultiverseCore.api.WorldPurger;
 import com.onarandombox.MultiverseCore.event.MVWorldDeleteEvent;
+import com.onarandombox.MultiverseCore.generators.InternalChunkGeneratorManager;
 import org.bukkit.Bukkit;
 import org.bukkit.GameRule;
 import org.bukkit.Location;
@@ -257,7 +258,12 @@ public class WorldManager implements MVWorldManager {
 
         // TODO: Use the fancy kind with the commandSender
         if (generator != null && generator.length() != 0) {
-            c.generator(generator);
+            //CustomGenerators start
+            if(generator.startsWith("multiverse:"))
+                c.generator(InternalChunkGeneratorManager.get().getGenerator(generator.split(":")[1]));
+            else
+                c.generator(generator);
+            //CustomGenerators end
         }
         c.environment(env);
         if (type != null) {
@@ -305,7 +311,11 @@ public class WorldManager implements MVWorldManager {
         if (generator == null) {
             return null;
         }
-
+        //CustomGenerators start
+        if(generator.equalsIgnoreCase("multiverse")){
+            return InternalChunkGeneratorManager.get().getGenerator(generatorID);
+        }
+        //CustomGenerators end
         final Plugin myPlugin = this.plugin.getServer().getPluginManager().getPlugin(generator);
         if (myPlugin == null) {
             return null;