/*
* This library is part of OpenCms -
* the Open Source Content Management System
*
* Copyright (c) Alkacon Software GmbH (http://www.alkacon.com)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* For further information about Alkacon Software GmbH, please see the
* company website: http://www.alkacon.com
*
* For further information about OpenCms, please see the
* project website: http://www.opencms.org
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.opencms.main;
import org.opencms.db.CmsSecurityManager;
import org.opencms.publish.CmsPublishJobRunning;
import org.opencms.publish.CmsPublishManager;
import org.opencms.report.A_CmsReportThread;
import org.opencms.util.CmsUUID;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import org.apache.commons.logging.Log;
/**
* The OpenCms "Grim Reaper" thread store were all system Threads are maintained.<p>
*
* This thread executes all 60 seconds and checks if report threads are still active.
* A report thread usually waits for a user to get the contents written to the report.
* However, if the user does not request the reports content (e.g. because the
* browser was closed), then the report thread becomes abandoned. This Grim Reaper
* will collect all such abandoned report threads and remove them after further
* 60 seconds.<p>
*
* Moreover, the Grim Reaper checks for all invalid user sessions that have times out for
* 5 or more minutes, and removes them as well.<p>
*
* @since 6.0.0
*/
public final class CmsThreadStore extends Thread {
/** The log object for this class. */
private static final Log LOG = CmsLog.getLog(CmsThreadStore.class);
/** The number of milliseconds in a minute. */
private static final int ONE_MINUTE_IN_MILLIS = 60000;
/** The interval, in minutes, for checking threads. */
private static final int UPDATE_MINUTES_INTERVAL = 5;
/** Indicates that this thread store is alive. */
private boolean m_alive;
/** The security manager instance. */
private CmsSecurityManager m_securityManager;
/** A map to store all system Threads in. */
private Map<CmsUUID, A_CmsReportThread> m_threads;
/**
* Hides the public constructor.<p>
*
* @param securityManager needed for scheduling "undercover-jobs"
* that increase stability and fault tolerance
*/
protected CmsThreadStore(CmsSecurityManager securityManager) {
super(new ThreadGroup("OpenCms Thread Store"), "OpenCms: Grim Reaper");
setDaemon(true);
// Hashtable is still the most efficient form of a synchronized HashMap
m_threads = new Hashtable<CmsUUID, A_CmsReportThread>();
m_alive = true;
m_securityManager = securityManager;
start();
}
/**
* Adds a Thread to this Thread store.<p>
*
* @param thread the Thread to add
*/
public void addThread(A_CmsReportThread thread) {
m_threads.put(thread.getUUID(), thread);
if (LOG.isDebugEnabled()) {
dumpThreads();
}
}
/**
* Retrieves a Thread from this Thread store.<p>
*
* @param key the key of the Thread to retrieve
* @return the Thread form this Thread store that matches the given key
*/
public A_CmsReportThread retrieveThread(CmsUUID key) {
if (LOG.isDebugEnabled()) {
dumpThreads();
}
return m_threads.get(key);
}
/**
* @see java.lang.Runnable#run()
*/
@Override
public void run() {
boolean checkPublishQueue = true;
int minutesForCheck = 0;
while (m_alive) {
// the Grim Reaper is eternal, of course
try {
// one minute sleep time
sleep(ONE_MINUTE_IN_MILLIS);
} catch (InterruptedException e) {
// let's go on reaping...
}
handleDoomedThreads();
// check the session manager for invalid sessions not removed for whatever reason
minutesForCheck++;
if (minutesForCheck < UPDATE_MINUTES_INTERVAL) {
continue;
}
minutesForCheck = 0;
checkPublishQueue = !checkPublishQueue;
// work every n minutes
validateSessions();
persistData();
if (checkPublishQueue) {
// every 2*n minutes
checkPublishQueue();
}
}
}
/**
* Checks the publish queue for abandoned publish jobs.<p>
*/
protected void checkPublishQueue() {
// check the publish manager if the current thread is still active
try {
CmsPublishManager publishManager = OpenCms.getPublishManager();
if (publishManager == null) {
// this can happen during shutdown
return;
}
// get the current publish job
CmsPublishJobRunning publishJob = publishManager.getCurrentPublishJob();
if (publishJob == null) {
// try to start next job
publishManager.checkCurrentPublishJobThread();
return;
}
// get the thread id of the current publish job
CmsUUID uid = publishJob.getThreadUUID();
if ((uid == null) || (uid.isNullUUID())) {
return;
}
// find the thread
A_CmsReportThread thread = m_threads.get(uid);
if (thread == null) {
return;
}
// check if the report still has output and so is active
if (System.currentTimeMillis() - thread.getLastEntryTime() > UPDATE_MINUTES_INTERVAL * ONE_MINUTE_IN_MILLIS) {
// remove it
m_threads.remove(thread);
// abandon thread
publishManager.abandonThread();
}
} catch (Throwable t) {
LOG.error(Messages.get().getBundle().key(Messages.LOG_THREADSTORE_CHECK_PUBLISH_THREAD_ERROR_0), t);
}
}
/**
* Handles doomed threads.<p>
*/
protected void handleDoomedThreads() {
try {
Iterator<CmsUUID> i = m_threads.keySet().iterator();
Set<CmsUUID> doomed = new HashSet<CmsUUID>();
// first collect all doomed Threads
while (i.hasNext()) {
CmsUUID key = i.next();
A_CmsReportThread thread = m_threads.get(key);
if (thread.isDoomed()) {
doomed.add(key);
if (LOG.isDebugEnabled()) {
LOG.debug(Messages.get().getBundle().key(
Messages.LOG_THREADSTORE_DOOMED_2,
thread.getName(),
thread.getUUID()));
}
}
}
i = doomed.iterator();
// no remove all doomed Threads from the Thread store
while (i.hasNext()) {
m_threads.remove(i.next());
}
if (LOG.isDebugEnabled()) {
dumpThreads();
}
} catch (Throwable t) {
// the Grim Reaper must not be stopped by any error
LOG.error(Messages.get().getBundle().key(Messages.LOG_THREADSTORE_CHECK_THREADS_ERROR_0), t);
}
}
/**
* Takes care of the persistence of data normally held in memory.<p>
*/
protected void persistData() {
try {
// save the resource locks to db
m_securityManager.writeLocks();
// save the log entries to db
m_securityManager.updateLog();
} catch (Throwable t) {
if (LOG.isErrorEnabled()) {
LOG.error(
org.opencms.lock.Messages.get().getBundle().key(org.opencms.lock.Messages.ERR_WRITE_LOCKS_0),
t);
}
}
}
/**
* Shut down this thread store.<p>
*/
protected synchronized void shutDown() {
m_alive = false;
interrupt();
}
/**
* Checks for invalid sessions.<p>
*/
protected void validateSessions() {
try {
CmsSessionManager sessionInfoManager = OpenCms.getSessionManager();
if (sessionInfoManager != null) {
// will be null if only the shell is running
sessionInfoManager.validateSessionInfos();
}
} catch (Throwable t) {
LOG.error(Messages.get().getBundle().key(Messages.LOG_THREADSTORE_CHECK_SESSIONS_ERROR_0), t);
}
}
/**
* Method to dump all currently known Threads.<p>
*/
private void dumpThreads() {
if (LOG.isDebugEnabled()) {
StringBuffer b = new StringBuffer(512);
Iterator<CmsUUID> i = m_threads.keySet().iterator();
while (i.hasNext()) {
CmsUUID key = i.next();
A_CmsReportThread thread = m_threads.get(key);
b.append(thread.getName());
b.append(" - ");
b.append(thread.getUUID());
b.append('\n');
}
LOG.debug(Messages.get().getBundle().key(
Messages.LOG_THREADSTORE_POOL_CONTENT_2,
new Integer(m_threads.size()),
b.toString()));
}
}
}