/*

 * Copyright (c) 2000, 2001, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.print;

import java.util.Vector;

import javax.print.PrintService;

import javax.print.attribute.PrintServiceAttributeSet;

import javax.print.attribute.HashPrintServiceAttributeSet;

import javax.print.event.PrintServiceAttributeEvent;

import javax.print.event.PrintServiceAttributeListener;

/*

 * A utility class usable by all print services for managing listeners

 * The services create an instance and delegate the listener callback

 * management to this class. The ServiceNotifier calls back to the service

 * to obtain the state of the attributes and notifies the listeners of

 * any changes.

 */

class ServiceNotifier extends Thread {

    private PrintService service;

    private Vector listeners;

    private boolean stop = false;

    private PrintServiceAttributeSet lastSet;

    ServiceNotifier(PrintService service) {

        super(service.getName() + " notifier");

        this.service = service;

        listeners = new Vector();

        try {

              setPriority(Thread.NORM_PRIORITY-1);

              setDaemon(true);

              start();

        } catch (SecurityException e) {

        }

    }

    void addListener(PrintServiceAttributeListener listener) {

        synchronized (this) {

            if (listener == null || listeners == null) {

                return;

            }

            listeners.add(listener);

        }

    }

    void removeListener(PrintServiceAttributeListener listener) {

         synchronized (this) {

            if (listener == null || listeners == null) {

                return;

            }

            listeners.remove(listener);

        }

    }

   boolean isEmpty() {

     return (listeners == null || listeners.isEmpty());

   }

   void stopNotifier() {

      stop = true;

   }

    /* If a service submits a job it may call this method which may prompt

     * immediate notification of listeners.

     */

    void wake() {

        try {

            interrupt();

        } catch (SecurityException e) {

        }

    }

   /* A heuristic is used to calculate sleep time.

     * 10 times the time taken to loop through all the listeners, with

     * a minimum of 15 seconds. Ensures this won't take more than 10%

     * of available time.

     */

    public void run() {

       long minSleepTime = 15000;

       long sleepTime = 2000;

       HashPrintServiceAttributeSet attrs;

       PrintServiceAttributeEvent attrEvent;

       PrintServiceAttributeListener listener;

       PrintServiceAttributeSet psa;

       while (!stop) {

           try {

                Thread.sleep(sleepTime);

           } catch (InterruptedException e) {

           }

           synchronized (this) {

               if (listeners == null) {

                   continue;

               }

               long startTime = System.currentTimeMillis();

               if (listeners != null) {

                    if (service instanceof AttributeUpdater) {

                       psa =

                          ((AttributeUpdater)service).getUpdatedAttributes();

                    } else {

                       psa = service.getAttributes();

                    }

                    if (psa != null && !psa.isEmpty()) {

                        for (int i = 0; i < listeners.size() ; i++) {

                            listener = (PrintServiceAttributeListener)

                                listeners.elementAt(i);

                            attrs =

                                new HashPrintServiceAttributeSet(psa);

                            attrEvent =

                                new PrintServiceAttributeEvent(service, attrs);

                            listener.attributeUpdate(attrEvent);

                        }

                    }

               }

               sleepTime = (System.currentTimeMillis()-startTime)*10;

               if (sleepTime < minSleepTime) {

                   sleepTime = minSleepTime;

               }

           }

       }

    }

}