001    /**
002     * Copyright (c) 2000-2012 Liferay, Inc. All rights reserved.
003     *
004     * This library is free software; you can redistribute it and/or modify it under
005     * the terms of the GNU Lesser General Public License as published by the Free
006     * Software Foundation; either version 2.1 of the License, or (at your option)
007     * any later version.
008     *
009     * This library is distributed in the hope that it will be useful, but WITHOUT
010     * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
011     * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
012     * details.
013     */
014    
015    package com.liferay.portal.kernel.notifications;
016    
017    import com.liferay.portal.kernel.log.Log;
018    import com.liferay.portal.kernel.log.LogFactoryUtil;
019    
020    import java.util.List;
021    import java.util.concurrent.CopyOnWriteArrayList;
022    import java.util.concurrent.atomic.AtomicLong;
023    
024    /**
025     * @author Edward Han
026     */
027    public abstract class BaseChannelImpl implements Channel {
028    
029            public void cleanUp() throws ChannelException {
030                    long currentTime = System.currentTimeMillis();
031    
032                    long nextCleanUpTime = _nextCleanUpTime.get();
033    
034                    if ((currentTime > nextCleanUpTime) &&
035                            _nextCleanUpTime.compareAndSet(
036                                    nextCleanUpTime, currentTime + _cleanUpInterval)) {
037    
038                            try {
039                                    doCleanUp();
040                            }
041                            catch (ChannelException ce) {
042                                    throw ce;
043                            }
044                            catch (Exception e) {
045                                    throw new ChannelException(e);
046                            }
047                    }
048            }
049    
050            public void close() throws ChannelException {
051                    flush();
052            }
053    
054            public long getCompanyId() {
055                    return _companyId;
056            }
057    
058            public List<NotificationEvent> getNotificationEvents()
059                    throws ChannelException {
060    
061                    return getNotificationEvents(true);
062            }
063    
064            public long getUserId() {
065                    return _userId;
066            }
067    
068            public boolean hasNotificationEvents() {
069                    try {
070                            List<NotificationEvent> notificationEvents = getNotificationEvents(
071                                    false);
072    
073                            if (!notificationEvents.isEmpty()) {
074                                    return true;
075                            }
076                    }
077                    catch (ChannelException ce) {
078                            if (_log.isErrorEnabled()) {
079                                    _log.error("Unable to fetch notifications", ce);
080                            }
081                    }
082    
083                    return false;
084            }
085    
086            public void registerChannelListener(ChannelListener channelListener) {
087                    _channelListeners.add(channelListener);
088    
089                    if (hasNotificationEvents()) {
090                            notifyChannelListeners();
091                    }
092            }
093    
094            public void setCleanUpInterval(long cleanUpInterval) {
095                    _cleanUpInterval = cleanUpInterval;
096            }
097    
098            public void unregisterChannelListener(ChannelListener channelListener) {
099                    _channelListeners.remove(channelListener);
100    
101                    channelListener.channelListenerRemoved(_userId);
102            }
103    
104            protected BaseChannelImpl(long companyId, long usedId) {
105                    _companyId = companyId;
106                    _userId = usedId;
107            }
108    
109            protected abstract void doCleanUp() throws Exception;
110    
111            protected void notifyChannelListeners() {
112                    for (ChannelListener channelListener : _channelListeners) {
113                            channelListener.notificationEventsAvailable(_userId);
114                    }
115            }
116    
117            private static Log _log = LogFactoryUtil.getLog(BaseChannelImpl.class);
118    
119            private List<ChannelListener> _channelListeners =
120                    new CopyOnWriteArrayList<ChannelListener>();
121            private long _cleanUpInterval;
122            private long _companyId;
123            private AtomicLong _nextCleanUpTime = new AtomicLong();
124            private long _userId;
125    
126    }