Preload chunks

LJVehicleListener.java

package com.narrowtux.longjourney;

import org.bukkit.Chunk;
import org.bukkit.Location;
import org.bukkit.event.vehicle.VehicleListener;
import org.bukkit.event.vehicle.VehicleMoveEvent;
import org.bukkit.util.Vector;

public class LJVehicleListener extends VehicleListener {
	
	@Override
	public void onVehicleMove(VehicleMoveEvent event) {
		Location to = event.getTo();
		Chunk c = to.getBlock().getChunk();
		int x = c.getX();
		int z = c.getZ();
		LongJourney.instance.touch(c);
		
		Vector dir = event.getVehicle().getVelocity();
		dir = dir.normalize();
		x += Math.round(dir.getX());
		z += Math.round(dir.getZ());
		LongJourney.instance.touch(to.getWorld().getChunkAt(x, z));
		
		for(int i = -3; i<=3; i++) {
			for(int j = -3; j<=3; j++) {
				c.getWorld().loadChunk(c.getX() + i, c.getZ() + j);
			}
		}
	}
}

LJWorldListener.java

package com.narrowtux.longjourney;

import org.bukkit.event.world.ChunkLoadEvent;
import org.bukkit.event.world.ChunkUnloadEvent;
import org.bukkit.event.world.WorldListener;

public class LJWorldListener extends WorldListener {
	
	public static final int KEEP_TIME = 1 * 60 * 1000;

	@Override
	public void onChunkUnload(ChunkUnloadEvent event) {
		if(LongJourney.instance.isTouched(event.getChunk())) {
			event.setCancelled(true);
		} else {
			LongJourney.instance.lastTouched.remove(event.getChunk());
		}
	}
}

LongJourney.java

package com.narrowtux.longjourney;
import java.util.HashMap;

import org.bukkit.Bukkit;
import org.bukkit.Chunk;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.event.Event.Priority;
import org.bukkit.event.Event.Type;
import org.bukkit.plugin.PluginManager;
import org.bukkit.plugin.java.JavaPlugin;


public class LongJourney extends JavaPlugin {
	
	public static LongJourney instance;
	public HashMap<Integer, Long> lastTouched = new HashMap<Integer, Long>();
	private LJVehicleListener vehicleListener = new LJVehicleListener();
	private LJWorldListener worldListener = new LJWorldListener();

	@Override
	public void onDisable() {
		
	}

	@Override
	public void onEnable() {
		instance = this;
		PluginManager pm = Bukkit.getPluginManager();
		pm.registerEvent(Type.VEHICLE_MOVE, vehicleListener, Priority.Normal, instance);
		pm.registerEvent(Type.CHUNK_UNLOAD, worldListener, Priority.Highest, instance);
	}
	
	public void touch(Chunk c) {
		lastTouched.put(getHash(c), System.currentTimeMillis());
	}
	
	public boolean isTouched(Chunk c) {
		Long time = lastTouched.get(getHash(c));
		if(time != null)
		{
			return System.currentTimeMillis() - LJWorldListener.KEEP_TIME < time;
		}
		return false;
	}

	private Integer getHash(Chunk c) {
		return 1001 * c.getX() + c.getZ();
	}

	@Override
	public boolean onCommand(CommandSender sender, Command command,
			String label, String[] args) {
		if(command.getName().equals("loadchunk")) {
			int x = Integer.valueOf(args[0]);
			int z = Integer.valueOf(args[1]);
			if(sender instanceof Player) {
				((Player)sender).getWorld().loadChunk(x, z);
			}
		}
		return true;
	}

}