Moved main loop into FixedRate scheduler. Added sync lock on runnable.

2006Redone Server/src/main/java/com/rebotted/GameEngine.java

@@ -3,6 +3,11 @@ package com.rebotted;
 import java.io.File;
 import java.io.IOException;
 import java.net.InetSocketAddress;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 
 import org.apache.mina.common.IoAcceptor;
 import org.apache.mina.transport.socket.nio.SocketAcceptor;
@@ -73,6 +78,8 @@ public class GameEngine {
 	public static FightCaves fightCaves = new FightCaves();
 	private static PestControl pestControl = new PestControl();
 	public static Trawler trawler = new Trawler();	
+	private final static ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
+	private final static Lock lock = new ReentrantLock();
 
 	/**
 	 * Port and Cycle rate.
@@ -145,12 +152,27 @@ public class GameEngine {
 		 */
 		System.out.println("Server listening on port " + serverlistenerPort);
 
+		/**
+		 * Main Server Tick
+		 * 
+		 * This scheduler will tick once every 600ms. If the previous tick takes
+		 * 300ms to execute, this scheduler will wait 300ms only before the next
+		 * tick.
+		 * 
+		 * Each tick, it will attempt to get a lock on the main server thread.
+		 * Without locking this runnable, multiple ticks could occur at once.
+		 */
+		scheduler.scheduleAtFixedRate(new Runnable() {
+			public void run() {
+				if (lock.tryLock()) {
+					synchronized (lock) {
 						/**
 						 * Main Server Tick
 						 */
 						try {
-			while (!GameEngine.shutdownServer) {
+							if (GameEngine.shutdownServer) {
-					Thread.sleep(600);
+								scheduler.shutdown();
+							}
 							itemHandler.process();
 							playerHandler.process();
 							npcHandler.process();
@@ -161,20 +183,20 @@ public class GameEngine {
 							pestControl.process();
 							CycleEventHandler.getSingleton().process();
 							PlayersOnlineWebsite.addUpdatePlayersOnlineTask();
-				RegisteredAccsWebsite.addUpdateRegisteredUsersTask();
+							RegisteredAccsWebsite
+									.addUpdateRegisteredUsersTask();
 							DiscordActivity.updateActivity();
-				if (System.currentTimeMillis() - lastMassSave > 300000) {
+							if (System.currentTimeMillis()
+									- lastMassSave > 300000) {
 								for (Player p : PlayerHandler.players) {
 									if (p == null) {
 										continue;
 									}
 									PlayerSave.saveGame((Client) p);
-						System.out.println("Saved game for " + p.playerName
+									System.out.println("Saved game for " + p.playerName + ".");
-								+ ".");
 									lastMassSave = System.currentTimeMillis();
 								}
 							}
-            }
 						} catch (Exception ex) {
 							ex.printStackTrace();
 							System.out.println("A fatal exception has been thrown!");
@@ -190,8 +212,18 @@ public class GameEngine {
 								}
 								PlayerSave.saveGame((Client) p);
 								System.out.println("Saved game for " + p.playerName + ".");
+								scheduler.shutdown(); // Kills the tickloop thread if Exception is thrown.
 							}
 						}
+					}
+				} else {
+					System.out.println("Can't Keep up! Did the system time change or is the server overloaded?");
+				}
+			}
+		}, 0, GameConstants.CYCLE_TIME, TimeUnit.MILLISECONDS);
+		
+		
+		
 		acceptor = null;
 		connectionHandler = null;
 		sac = null;