001    /**
002     * Copyright (c) 2000-2013 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            @Override
030            public void cleanUp() throws ChannelException {
031                    long currentTime = System.currentTimeMillis();
032    
033                    long nextCleanUpTime = _nextCleanUpTime.get();
034    
035                    if ((currentTime > nextCleanUpTime) &&
036                            _nextCleanUpTime.compareAndSet(
037                                    nextCleanUpTime, currentTime + _cleanUpInterval)) {
038    
039                            try {
040                                    doCleanUp();
041                            }
042                            catch (ChannelException ce) {
043                                    throw ce;
044                            }
045                            catch (Exception e) {
046                                    throw new ChannelException(e);
047                            }
048                    }
049            }
050    
051            @Override
052            public void close() throws ChannelException {
053                    flush();
054            }
055    
056            public long getCompanyId() {
057                    return _companyId;
058            }
059    
060            @Override
061            public List<NotificationEvent> getNotificationEvents()
062                    throws ChannelException {
063    
064                    return getNotificationEvents(true);
065            }
066    
067            @Override
068            public long getUserId() {
069                    return _userId;
070            }
071    
072            public boolean hasNotificationEvents() {
073                    try {
074                            List<NotificationEvent> notificationEvents = getNotificationEvents(
075                                    false);
076    
077                            if (!notificationEvents.isEmpty()) {
078                                    return true;
079                            }
080                    }
081                    catch (ChannelException ce) {
082                            if (_log.isErrorEnabled()) {
083                                    _log.error("Unable to fetch notifications", ce);
084                            }
085                    }
086    
087                    return false;
088            }
089    
090            @Override
091            public void registerChannelListener(ChannelListener channelListener) {
092                    _channelListeners.add(channelListener);
093    
094                    if (hasNotificationEvents()) {
095                            notifyChannelListeners();
096                    }
097            }
098    
099            public void setCleanUpInterval(long cleanUpInterval) {
100                    _cleanUpInterval = cleanUpInterval;
101            }
102    
103            @Override
104            public void unregisterChannelListener(ChannelListener channelListener) {
105                    _channelListeners.remove(channelListener);
106    
107                    channelListener.channelListenerRemoved(_userId);
108            }
109    
110            protected BaseChannelImpl(long companyId, long usedId) {
111                    _companyId = companyId;
112                    _userId = usedId;
113            }
114    
115            protected abstract void doCleanUp() throws Exception;
116    
117            protected void notifyChannelListeners() {
118                    for (ChannelListener channelListener : _channelListeners) {
119                            channelListener.notificationEventsAvailable(_userId);
120                    }
121            }
122    
123            private static Log _log = LogFactoryUtil.getLog(BaseChannelImpl.class);
124    
125            private List<ChannelListener> _channelListeners =
126                    new CopyOnWriteArrayList<ChannelListener>();
127            private long _cleanUpInterval;
128            private long _companyId;
129            private AtomicLong _nextCleanUpTime = new AtomicLong();
130            private long _userId;
131    
132    }