/*
 *
 * Copyright (c) 2000 Scott Oaks and Henry Wong. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and
 * without fee is hereby granted.
 *
 * This sample source code is provided for example only,
 * on an unsupported, as-is basis. 
 *
 * AUTHOR MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. AUTHOR SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
 * CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
 * PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
 * NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
 * SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
 * SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
 * PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  AUTHOR
 * SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
 * HIGH RISK ACTIVITIES.
 */


import java.util.*;

import com.sun.jini.thread.*;
import com.sun.jini.lease.landlord.*;

public class Expirer implements LeaseManager {

    Landlord landlord;
    WakeupManager manager;
    HashMap tickets;

    // Instances of this class are scheduled to run at a specific
    // time by the wakeup manager -- they will run when the lease
    // has expired, and they will cancel the lease. A lease renewal
    // will remove the task from the wakeup managers queue
    class ExpirerTask implements Runnable {
        LeasedResource resource;

        ExpirerTask(LeasedResource r) {
            resource = r;
        }
        public void run() {
            long now = System.currentTimeMillis();
            long expir = resource.getExpiration();
            if (expir > now) {
                // It was renewed, but we didn't cancel the task in time.
                WakeupManager.Ticket ticket = manager.schedule(expir, this);
                tickets.put(resource, ticket);
            }
            else try {
                landlord.cancel(resource.getCookie());
            } catch (Exception e) {
            }
        }
    }

    public Expirer(Landlord l) {
        landlord = l;
        tickets = new HashMap(13);
        manager = new WakeupManager();
    }

    // The lease has been renewed. A side-effect of registering
    // the new duration will be to cancel the old task from the
    // taskmanager queue.
    public void renewed(LeasedResource resource,
                        long duration, long oldExpiration) {
        register(resource, duration);
    }

    // A lease has been created or renewed. Cancel its old
    // expiration task and create a new expiration task to
    // cancel the lease after it expires.
    public void register(LeasedResource resource, long duration) {
        WakeupManager.Ticket ticket;

        ticket = (WakeupManager.Ticket) tickets.remove(resource);
        if (ticket != null)
            manager.cancel(ticket);
        ExpirerTask task = new ExpirerTask(resource);
        ticket = manager.schedule(resource.getExpiration(), task);
        tickets.put(resource, ticket);
    }
}