Clean up World Gen Threads after termination

core/src/main/java/com/seibel/distanthorizons/core/generation/WorldGenerationQueue.java

@@ -18,6 +18,7 @@ import com.seibel.distanthorizons.core.render.renderer.DebugRenderer;
 import com.seibel.distanthorizons.core.render.renderer.IDebugRenderable;
 import com.seibel.distanthorizons.core.util.ThreadUtil;
 import com.seibel.distanthorizons.core.util.objects.DhThreadFactory;
+import com.seibel.distanthorizons.core.util.objects.RateLimitedThreadPoolExecutor;
 import com.seibel.distanthorizons.core.util.objects.UncheckedInterruptedException;
 import com.seibel.distanthorizons.core.util.LodUtil;
 import com.seibel.distanthorizons.core.wrapperInterfaces.IWrapperFactory;
@@ -34,7 +35,7 @@ public class WorldGenerationQueue implements Closeable, IDebugRenderable
 {
 	private static final Logger LOGGER = DhLoggerBuilder.getLogger();
 	
-	public static final DhThreadFactory THREAD_FACTORY = new DhThreadFactory(ThreadUtil.THREAD_NAME_PREFIX + "Gen-Worker-Thread", Thread.MIN_PRIORITY);
+	public static final DhThreadFactory THREAD_FACTORY = new DhThreadFactory(ThreadUtil.THREAD_NAME_PREFIX + "World-Gen-Worker-Thread", Thread.MIN_PRIORITY);
 	
 	private final IDhApiWorldGenerator generator;
 	
@@ -73,7 +74,7 @@ public class WorldGenerationQueue implements Closeable, IDebugRenderable
 	private final HashMap<DhLodPos, StackTraceElement[]> alreadyGeneratedPosHashSet = new HashMap<>(MAX_ALREADY_GENERATED_COUNT);
 	private final Queue<DhLodPos> alreadyGeneratedPosQueue = new LinkedList<>();
 	
-	private static ExecutorService worldGeneratorThreadPool;
+	private static RateLimitedThreadPoolExecutor worldGeneratorThreadPool;
 	private static ConfigChangeListener<Integer> configListener;
 	
 	
@@ -527,6 +528,7 @@ public class WorldGenerationQueue implements Closeable, IDebugRenderable
 		}
 		
 		worldGeneratorThreadPool = ThreadUtil.makeRateLimitedThreadPool(threadPoolSize, THREAD_FACTORY, Config.Client.Advanced.MultiThreading.runTimeRatioForWorldGenerationThreads);
+		worldGeneratorThreadPool.setOnTerminatedEventHandler(WorldGenerationQueue::onWorldGenThreadPoolTerminated);
 	}
 	
 	/**
@@ -542,6 +544,12 @@ public class WorldGenerationQueue implements Closeable, IDebugRenderable
 		}
 	}
 	
+	private static void onWorldGenThreadPoolTerminated()
+	{
+		LOGGER.debug("World generator thread pool terminated. Suggesting the JVM runs a garbage collection to clean up any loose world generation objects...");
+		System.gc();
+	}
+	
 	
 	
 	//=========//

core/src/main/java/com/seibel/distanthorizons/core/util/objects/RateLimitedThreadPoolExecutor.java

@@ -15,6 +15,8 @@ public class RateLimitedThreadPoolExecutor extends ThreadPoolExecutor
 	/** How long it took this thread to run its last task */
 	private final ThreadLocal<Long> lastRunDurationNanoTimeRef = ThreadLocal.withInitial(() -> -1L);
 	
+	private Runnable onTerminatedEventHandler = null;
+	
 	
 	
 	//==============//
@@ -63,4 +65,23 @@ public class RateLimitedThreadPoolExecutor extends ThreadPoolExecutor
 		this.lastRunDurationNanoTimeRef.set(System.nanoTime() - this.runStartNanoTimeRef.get());
 	}
 	
+	@Override
+	protected void terminated() 
+	{
+		super.terminated();
+		if (this.onTerminatedEventHandler != null)
+		{
+			this.onTerminatedEventHandler.run();
+		}
+	}
+	
+	
+	
+	//==============//
+	// custom logic //
+	//==============//
+	
+	/** only one event handler can be present at a time */
+	public void setOnTerminatedEventHandler(Runnable runnable) { this.onTerminatedEventHandler = runnable; }
+	
 }