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/*
This file is part of Subsonic.
Subsonic is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Subsonic 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 for more details.
You should have received a copy of the GNU General Public License
along with Subsonic. If not, see <http://www.gnu.org/licenses/>.
Copyright 2009 (C) Sindre Mehus
*/
package net.sourceforge.subsonic.ajax;
import net.sourceforge.subsonic.Logger;
import net.sourceforge.subsonic.service.SecurityService;
import net.sourceforge.subsonic.util.BoundedList;
import org.apache.commons.lang.StringUtils;
import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;
import javax.servlet.http.HttpServletRequest;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Date;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
/**
* Provides AJAX-enabled services for the chatting.
* This class is used by the DWR framework (http://getahead.ltd.uk/dwr/).
*
* @author Sindre Mehus
*/
public class ChatService {
private static final Logger LOG = Logger.getLogger(ChatService.class);
private static final String CACHE_KEY = "1";
private static final int MAX_MESSAGES = 10;
private static final long TTL_MILLIS = 3L * 24L * 60L * 60L * 1000L; // 3 days.
private final LinkedList<Message> messages = new BoundedList<Message>(MAX_MESSAGES);
private SecurityService securityService;
private long revision = System.identityHashCode(this);
/**
* Invoked by Spring.
*/
public void init() {
// Delete old messages every hour.
ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor();
Runnable runnable = new Runnable() {
public void run() {
removeOldMessages();
}
};
executor.scheduleWithFixedDelay(runnable, 0L, 3600L, TimeUnit.SECONDS);
}
private synchronized void removeOldMessages() {
long now = System.currentTimeMillis();
for (Iterator<Message> iterator = messages.iterator(); iterator.hasNext();) {
Message message = iterator.next();
if (now - message.getDate().getTime() > TTL_MILLIS) {
iterator.remove();
revision++;
}
}
}
public synchronized void addMessage(String message) {
WebContext webContext = WebContextFactory.get();
doAddMessage(message, webContext.getHttpServletRequest());
}
public synchronized void doAddMessage(String message, HttpServletRequest request) {
String user = securityService.getCurrentUsername(request);
message = StringUtils.trimToNull(message);
if (message != null && user != null) {
messages.addFirst(new Message(message, user, new Date()));
revision++;
}
}
public synchronized void clearMessages() {
messages.clear();
revision++;
}
/**
* Returns all messages, but only if the given revision is different from the
* current revision.
*/
public synchronized Messages getMessages(long revision) {
if (this.revision != revision) {
return new Messages(new ArrayList<Message>(messages), this.revision);
}
return null;
}
public void setSecurityService(SecurityService securityService) {
this.securityService = securityService;
}
public static class Messages implements Serializable {
private static final long serialVersionUID = -752602719879818165L;
private final List<Message> messages;
private final long revision;
public Messages(List<Message> messages, long revision) {
this.messages = messages;
this.revision = revision;
}
public List<Message> getMessages() {
return messages;
}
public long getRevision() {
return revision;
}
}
public static class Message implements Serializable {
private static final long serialVersionUID = -1907101191518133712L;
private final String content;
private final String username;
private final Date date;
public Message(String content, String username, Date date) {
this.content = content;
this.username = username;
this.date = date;
}
public String getContent() {
return content;
}
public String getUsername() {
return username;
}
public Date getDate() {
return date;
}
}
}
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