scheduler.java

p2p仿真器。开发者可以工作在覆盖层中进行创造和测试逻辑算法或者创建和测试新的服务。PlanetSim还可以将仿真代码平稳转换为在Internet上的实验代码

package planet.simulate;

import planet.util.OrderedList;
import java.util.*;

/**
 * This class implements the interface IScheduler and manage
 * events to produce to simulated network.
 * @author <a href="mailto: [e-mail]">Pedro Garcia</a>
 * @author <a href="mailto: [e-mail]">Jordi Pujol</a>
 * 14-jul-2005
 */
/**
 * @author <a href="mailto: [e-mail]">Jordi Pujol</a>
 * 14-jul-2005
 */
public class Scheduler implements IScheduler, java.io.Serializable {

    /**
     * The specified internal value for the attribute <b>nextAlarm</b> to
     * show that there are no more alerts (events).
     */
    private static final int NO_MORE_ALERTS = -1;
    /**
     * Shows the time step for the next alarm (event).
     */
	private int nextAlarm;
    /**
     * Ordered list of alarms (events).
     */
	private OrderedList alarms = null;
	

    /**
     * Initializes this Scheduler.
     */
	public Scheduler(){
        nextAlarm = NO_MORE_ALERTS;
	}
	
    /**
     * Adds all the Event instances within <b>events</b> into the current
     * scheduler.
     * @param events Unordered list of events.
     * @see planet.simulate.IScheduler#addEvents(java.util.Vector)
     */
	public void addEvents(Vector events) {
        if (events == null || events.size()==0) return;
        
        Iterator it = events.iterator();

        Vector list = null;
        Event e = null;
        int time = 0;

        //adds the first element into the list.
        if (alarms == null)
        {
            list = new Vector();
            e = (Event) it.next();
            list.add(e);
            alarms = new OrderedList(list,e.getTime());
        }
        
        //adds the rest
        while (it.hasNext())
        {
			e = (Event) it.next();
			time = e.getTime();
			
			if (!alarms.contains(time)){
				list = new Vector();
				list.add(e);
				alarms.insert(new OrderedList(list,time));
			}else {
				list = (Vector)alarms.get(time);
				list.add(e);
			}
		}
		nextAlarm = alarms.value();
	}

    /**
     * Gets all alerts occurred at <b>time</b> time.
     * @param time Number of step which obtain all its alerts.
     * @return All alerts occurred at <b>time</b> time.
     * @see planet.simulate.IScheduler#getEvents(int)
     */
	public Vector getEvents(int time){
		Vector events = new Vector();
		Iterator it;
		
		if (nextAlarm==time)
        {
			Vector evts = (Vector)alarms.get(time);
			events.addAll(evts);
			alarms = alarms.pop();
			
            if (alarms == null)
                nextAlarm = NO_MORE_ALERTS;
            else
                nextAlarm = alarms.value();
		}
		return events;
	}
	
    /**
     * Shows if there are more alerts.
     * @return true if there are more alerts.
     * @see planet.simulate.IScheduler#hasNext()
     */
	public boolean hasNext() {
	  return nextAlarm != NO_MORE_ALERTS;
	}

    /**
     * Shows the string representation of the current scheduler.
     * @return The string representation of the current scheduler.
     * @see java.lang.Object#toString()
     */
    public String toString()
    {
        return "Scheduler: nextAlarm = "+nextAlarm+", alarms = "+alarms;
    }
}