source: java-rpg-server/ProcessingThread.java

import java.util.*;

/*
 * This thread handles events in the world such as monster movement and player movement and other things that do not require player input. It
 * also sends information to all players to notify them of changes in the world.
 */

public class ProcessingThread extends Thread {
        LostHavenServer server;

    public ProcessingThread(LostHavenServer main) {
        super("ProcessingThread");
        server = main;
    }
    
    public void run() {
        while(server.running) {
                updateWorld();
                //sendInfo();
                try {
                        Thread.sleep(1);
                }catch(InterruptedException ie) {
                        ie.printStackTrace();
                }
        }
        }
    
    private void updateWorld() {
        Iterator<String> iter = server.orderedOnline.iterator();
        Player p;
        Point loc, target;
        
        while(iter.hasNext()) {
                p = server.registered.get(iter.next());
                loc = p.getLoc();
                target = p.getTarget();
                
                if((System.currentTimeMillis()-p.getLastMoved())>=10) {
                        if(Point.dist(loc, target) <= p.getSpeed())
                                p.setLoc(target);
                        else {
                                int xChange = new Double(p.getSpeed()*(System.currentTimeMillis()-p.getLastMoved())*(target.getX()-loc.getX())/Point.dist(loc, target)/20).intValue();
                                int yChange = new Double(p.getSpeed()*(System.currentTimeMillis()-p.getLastMoved())*(target.getY()-loc.getY())/Point.dist(loc, target)/20).intValue();
                                
                                p.setLoc(new Point(p.getLoc().getX()+xChange, p.getLoc().getY()+yChange));
                        }
                        p.setLastMoved(System.currentTimeMillis());
                        server.sendAll(MessageType.Movement, p.getName()+" "+p.getLoc().toString());
                }
        }
    }
}