Maturing the border exemption; instead of a blanket exemption this starts a check task to see if the player's world has caught up with their portaled location.

pom.xml

@@ -3,7 +3,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>com.wimbli.WorldBorder</groupId>
 	<artifactId>WorldBorder</artifactId>
-	<version>1.8.7</version>
+	<version>1.8.8</version>
 	<name>WorldBorder</name>
 	<url>https://github.com/Brettflan/WorldBorder</url>
 	<issueManagement>
@@ -60,7 +60,7 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-compiler-plugin</artifactId>
-				<version>3.0</version>
+				<version>3.5.1</version>
 				<configuration>
 					<source>1.7</source>
 					<target>1.7</target>

src/main/java/com/wimbli/WorldBorder/BorderCheckTask.java

@@ -2,8 +2,9 @@ package com.wimbli.WorldBorder;
 
 import java.util.Collection;
 import java.util.Collections;
-import java.util.LinkedHashSet;
-import java.util.Set;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.UUID;
 
 import com.google.common.collect.ImmutableList;
 
@@ -36,31 +37,95 @@ public class BorderCheckTask implements Runnable
 		}
 	}
 
-	// track players who are being handled (moved back inside the border) already; needed since Bukkit is sometimes sending teleport events with the old (now incorrect) location still indicated, which can lead to a loop when we then teleport them thinking they're outside the border, triggering event again, etc.
-	private static Set<String> handlingPlayers = Collections.synchronizedSet(new LinkedHashSet<String>());
+	/** track players who are being handled (moved back inside the border) already; needed 
+	 * since Bukkit is sometimes sending teleport events with the old (now incorrect) location 
+	 * still indicated, which can lead to a loop when we then teleport them thinking they're 
+	 * outside the border, triggering event again, etc.
+	 */
+	private static Map<String, BukkitRunnable> handlingPlayers = Collections.synchronizedMap(new LinkedHashMap<String, BukkitRunnable>());
 
 	/**
 	 * In 1.9, there is a significant delay between teleportation event and when the player's location is actually updated.
 	 * However, the player world is updated immediately. This disconnection causes the regular checkPlayer to 
-	 * incorrectly test the player's prior-world location against the new-world location during that inbetween period.
+	 * incorrectly test the player's prior-world location against the new-world location during that amorphous
+	 * in-between period.
 	 * 
-	 * This function allows a temporary delay against the check to let Minecraft "catch up" the player's _real_ location.
+	 * This function allows a configurable recheck to let Minecraft "catch up" the player's <i>real</i> location.
+	 * 
+	 * In the meantime, the player is exempted from border crossing checks (and from spurious additional teleport event
+	 * checks).
+	 * 
+	 * Note that additional portal teleports (e.g. if the player immediately portals back) will reset
+	 * this check gracefully. 
+	 * 
+	 * @param player The player who is being exempted.
+	 * @param world The world the player is supposedly now in.
+	 * @param maxDelay The <i>maximum</i> ticks to spend exempting this player
+	 * @param recheckDelay The ticks to wait inbetween rechecks.
 	 */
-	public static void timedPlayerExemption(final Player player, long delay) {
-		handlingPlayers.add(player.getName().toLowerCase());
+	public static void timedPlayerExemption(final Player player, final String world, final long maxDelay, final long recheckDelay) {
 
-		new BukkitRunnable() {
-			private final String playerName = player.getName().toLowerCase();
-			@Override
-			public void run() {
-				handlingPlayers.remove(playerName);
-				if (Config.Debug())
-					Config.log("Exemption for " + playerName + " expired");
-			}
-		}.runTaskLater(WorldBorder.plugin, delay);
+		// Check for existing watch; cancel if one exists.
+		BukkitRunnable alreadyWatching = handlingPlayers.get(player.getName().toLowerCase());
+		if (alreadyWatching != null) {
+			try {
+				alreadyWatching.cancel(); 
+			} catch (IllegalStateException e){}
+		}
+		
+		alreadyWatching = new BukkitRunnable() {
+				private final String playerName = player.getName().toLowerCase();
+				private final UUID playerUUID = player.getUniqueId();
+				private long currentDelay = recheckDelay;
+				@Override
+				public void run() {
+					// Are we done checking?
+					if (currentDelay > maxDelay) {
+						this.cancel();
+						handlingPlayers.remove(playerName);
+						if (Config.Debug())
+							Config.log("Done watching " + playerName + ". They are in the hands of fate, now.");
+						return;
+					}
+					currentDelay += recheckDelay;
+					
+					// Is this player still online?
+					Player player = Bukkit.getPlayer(playerUUID);
+					if (player == null) { // assume offline 
+						this.cancel();
+						handlingPlayers.remove(playerName);
+						if (Config.Debug())
+							Config.log("Looks like " + playerName + " logged off. Suspending watch.");
+						return;
+					}
+					
+					// Are we still stuck between worlds?
+					Location loc = player.getLocation();
+					World worldObj = loc.getWorld();
+					if (world.equals(worldObj.getName())) {
+						// No, we made it!
+						this.cancel();
+						handlingPlayers.remove(playerName);
+						if (Config.Debug()) 
+							Config.log("Minecraft caught up with " + playerName + ". Ending watch.");
+						return;
+					}
+					
+					if (Config.Debug()) {
+						Config.log("Based on teleport " + playerName + " is in " + world +
+								" but Minecraft still thinks they are in " + worldObj.getName() +
+								". Checking again in " + recheckDelay);
+					}
+				}
+			};
+
+		// Store the exemption and start the recheck.
+		handlingPlayers.put(player.getName().toLowerCase(), alreadyWatching);
+		alreadyWatching.runTaskTimer(WorldBorder.plugin, recheckDelay, recheckDelay);
 
 		if (Config.Debug())
-			Config.log("Exempting " + player.getName().toLowerCase() + " for " + delay + " ticks.");
+			Config.log("Rechecking " + player.getName() + "'s world every " + 
+					recheckDelay + " ticks for " + maxDelay + " ticks.");
 	}
 
 	// set targetLoc only if not current player location; set returnLocationOnly to true to have new Location returned if they need to be moved to one, instead of directly handling it
@@ -80,11 +145,11 @@ public class BorderCheckTask implements Runnable
 			return null;
 
 		// if player is in bypass list (from bypass command), allow them beyond border; also ignore players currently being handled already
-		if (Config.isPlayerBypassing(player.getUniqueId()) || handlingPlayers.contains(player.getName().toLowerCase()))
+		if (Config.isPlayerBypassing(player.getUniqueId()) || handlingPlayers.containsKey(player.getName().toLowerCase()))
 			return null;
 
 		// tag this player as being handled so we can't get stuck in a loop due to Bukkit currently sometimes repeatedly providing incorrect location through teleport event
-		handlingPlayers.add(player.getName().toLowerCase());
+		handlingPlayers.put(player.getName().toLowerCase(), null);
 
 		Location newLoc = newLocation(player, loc, border, notify);
 		boolean handlingVehicle = false;

src/main/java/com/wimbli/WorldBorder/Config.java

@@ -56,6 +56,8 @@ public class Config
 	private static int fillMemoryTolerance = 500;
 	private static boolean preventBlockPlace = false;
 	private static boolean preventMobSpawn = false;
+	private static long maxExemptionTicks = 21l;
+	private static long portalRecheckTicks = 4l; // These together give 5 recheck chances over the course of a second.
 
 	// for monitoring plugin efficiency
 //	public static long timeUsed = 0;
@@ -539,6 +541,21 @@ public class Config
 
 		return false;
 	}
+	
+	
+	public static long getMaxExemptionTicks() {
+		return maxExemptionTicks;
+	}
+	public static void setMaxExemptionTicks(long maxExemptionTicks) {
+		Config.maxExemptionTicks = maxExemptionTicks;
+	}
+	
+	public static long getPortalRecheckTicks() {
+		return portalRecheckTicks;
+	}
+	public static void setPortalRecheckTicks(long portalRecheckTicks) {
+		Config.portalRecheckTicks = portalRecheckTicks;
+	}
 
 
 	public static String replaceAmpColors (String message)
@@ -600,6 +617,8 @@ public class Config
 		fillMemoryTolerance = cfg.getInt("fill-memory-tolerance", 500);
 		preventBlockPlace = cfg.getBoolean("prevent-block-place");
 		preventMobSpawn = cfg.getBoolean("prevent-mob-spawn");
+		maxExemptionTicks = cfg.getLong("max-exemption-ticks", 21l);
+		portalRecheckTicks = cfg.getLong("portal-recheck-ticks", 4l);
 
 		StartBorderTimer();
 
@@ -708,6 +727,8 @@ public class Config
 		cfg.set("fill-memory-tolerance", fillMemoryTolerance);
 		cfg.set("prevent-block-place", preventBlockPlace);
 		cfg.set("prevent-mob-spawn", preventMobSpawn);
+		cfg.set("max-exemption-ticks", maxExemptionTicks);
+		cfg.set("portal-recheck-ticks", portalRecheckTicks);
 
 		cfg.set("worlds", null);
 		for(Entry<String, BorderData> stringBorderDataEntry : borders.entrySet())
@@ -746,4 +767,5 @@ public class Config
 		if (logIt)
 			logConfig("Configuration saved.");
 	}
+
 }

src/main/java/com/wimbli/WorldBorder/WBListener.java

@@ -9,7 +9,6 @@ import org.bukkit.event.player.PlayerPortalEvent;
 import org.bukkit.event.world.ChunkLoadEvent;
 import org.bukkit.Location;
 
-
 public class WBListener implements Listener
 {
 	@EventHandler(priority = EventPriority.LOWEST, ignoreCancelled = true)
@@ -19,11 +18,9 @@ public class WBListener implements Listener
 		if (Config.KnockBack() == 0.0)
 			return;
 
-		if (Config.Debug())
-			Config.log("General Teleport cause: " + event.getCause().toString());
-
-		if (PlayerTeleportEvent.TeleportCause.NETHER_PORTAL == event.getCause()) {
-			Config.log("Skipping teleport management event - covered by onPlayerPortal");
+		if (event instanceof PlayerPortalEvent) { // Avoid overlapping management.
+			if (Config.Debug())
+				Config.log("Skipping teleport management event - covered by onPlayerPortal");
 			return;
 		}
 
@@ -55,7 +52,8 @@ public class WBListener implements Listener
 			event.setTo(newLoc);
 		}
 
-		BorderCheckTask.timedPlayerExemption(event.getPlayer(), 100l);
+		BorderCheckTask.timedPlayerExemption(event.getPlayer(), event.getTo().getWorld().getName(),
+				Config.getMaxExemptionTicks(), Config.getPortalRecheckTicks());
 	}
 
 	@EventHandler(priority = EventPriority.MONITOR)