Java tutorial
/* * 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.publish; import org.opencms.db.CmsDbContext; import org.opencms.db.CmsDriverManager; import org.opencms.file.CmsObject; import org.opencms.main.CmsException; import org.opencms.main.CmsLog; import org.opencms.main.OpenCms; import org.opencms.monitor.CmsMemoryMonitor; import java.util.ArrayList; import java.util.Collections; import java.util.Iterator; import java.util.List; import org.apache.commons.collections.Buffer; import org.apache.commons.collections.BufferUtils; import org.apache.commons.collections.buffer.TypedBuffer; import org.apache.commons.collections.buffer.UnboundedFifoBuffer; import org.apache.commons.logging.Log; /** * This queue contains all not jet started publish jobs.<p> * * @since 6.5.5 */ public class CmsPublishQueue { /** The log object for this class. */ private static final Log LOG = CmsLog.getLog(CmsPublishHistory.class); /** The publish engine. */ protected final CmsPublishEngine m_publishEngine; /** * Default constructor, for an empty queue.<p> * * @param publishEngine the publish engine instance */ protected CmsPublishQueue(final CmsPublishEngine publishEngine) { m_publishEngine = publishEngine; } /** * Creates the buffer used as publish queue.<p> * * @return the queue buffer */ public static Buffer getQueue() { return BufferUtils.synchronizedBuffer(TypedBuffer.decorate(new UnboundedFifoBuffer() { /** The serialization version id constant. */ private static final long serialVersionUID = 606444342980861724L; /** * Called when the queue is full to remove the oldest element.<p> * * @see org.apache.commons.collections.buffer.BoundedFifoBuffer#remove() */ @Override public Object remove() { CmsPublishJobInfoBean publishJob = (CmsPublishJobInfoBean) super.remove(); return publishJob; } }, CmsPublishJobInfoBean.class)); } /** * Aborts the given publish job.<p> * * @param publishJob the publish job to abort * * @return <code>true</code> if the publish job was found */ protected boolean abortPublishJob(CmsPublishJobInfoBean publishJob) { if (OpenCms.getMemoryMonitor().getCachedPublishJob(publishJob.getPublishHistoryId().toString()) != null) { // remove publish job from cache OpenCms.getMemoryMonitor().uncachePublishJob(publishJob); return true; } else { return false; } } /** * Pushes a new publish job with the given information in publish queue.<p> * * If possible, the publish job starts immediately.<p> * * @param publishJob the publish job to enqueue * * @throws CmsException if something goes wrong */ protected void add(CmsPublishJobInfoBean publishJob) throws CmsException { // set the queue status in the publish job publishJob.enqueue(); // add job to database if necessary if (OpenCms.getMemoryMonitor().requiresPersistency()) { CmsDbContext dbc = m_publishEngine.getDbContext(null); try { // this operation may in rare circumstances fail with a DB exception // if this is the case the publish job must NOT be in the queue m_publishEngine.getDriverManager().createPublishJob(dbc, publishJob); } catch (CmsException e) { dbc.rollback(); LOG.error(e.getLocalizedMessage(), e); throw e; } finally { dbc.clear(); } } // add publish job to cache OpenCms.getMemoryMonitor().cachePublishJob(publishJob); } /** * Returns an unmodifiable list representation of this queue.<p> * * @return a list of {@link CmsPublishJobEnqueued} objects */ protected List<CmsPublishJobEnqueued> asList() { List<CmsPublishJobInfoBean> cachedPublishJobs = OpenCms.getMemoryMonitor().getAllCachedPublishJobs(); List<CmsPublishJobEnqueued> result = new ArrayList<CmsPublishJobEnqueued>(cachedPublishJobs.size()); Iterator<CmsPublishJobInfoBean> it = cachedPublishJobs.iterator(); while (it.hasNext()) { CmsPublishJobInfoBean publishJob = it.next(); result.add(new CmsPublishJobEnqueued(publishJob)); } return Collections.unmodifiableList(result); } /** * Checks if the given job is already in the queue, this does only check for the identical job.<p> * * @param publishJob the publish job to check for * * @return true if the given job is already in the queue */ protected boolean contains(CmsPublishJobInfoBean publishJob) { List<CmsPublishJobInfoBean> l = OpenCms.getMemoryMonitor().getAllCachedPublishJobs(); if (l != null) { for (int i = 0; i < l.size(); i++) { CmsPublishJobInfoBean b = l.get(i); if (b == publishJob) { return true; } } } return false; } /** * Initializes the internal FIFO queue with publish jobs from the database.<p> * * @param adminCms an admin cms object * @param revive <code>true</code> if the publish queue should be revived from the database */ protected void initialize(CmsObject adminCms, boolean revive) { CmsDriverManager driverManager = m_publishEngine.getDriverManager(); try { OpenCms.getMemoryMonitor().flushCache(CmsMemoryMonitor.CacheType.PUBLISH_QUEUE); if (revive) { // read all pending publish jobs from the database CmsDbContext dbc = m_publishEngine.getDbContext(null); List<CmsPublishJobInfoBean> publishJobs = null; try { publishJobs = driverManager.readPublishJobs(dbc, 0L, 0L); } catch (Exception e) { dbc.rollback(); } finally { dbc.clear(); dbc = null; } for (Iterator<CmsPublishJobInfoBean> i = publishJobs.iterator(); i.hasNext();) { CmsPublishJobInfoBean job = i.next(); dbc = m_publishEngine.getDbContext(null); if (!job.isStarted()) { // add jobs not already started to queue again try { job.revive(adminCms, driverManager.readPublishList(dbc, job.getPublishHistoryId())); m_publishEngine.lockPublishList(job); OpenCms.getMemoryMonitor().cachePublishJob(job); } catch (CmsException exc) { // skip job dbc.rollback(); if (LOG.isErrorEnabled()) { LOG.error(Messages.get().getBundle().key(Messages.ERR_PUBLISH_JOB_INVALID_1, job.getPublishHistoryId()), exc); } m_publishEngine.getDriverManager().deletePublishJob(dbc, job.getPublishHistoryId()); } finally { dbc.clear(); } } else { try { // remove locks, set finish info and move job to history job.revive(adminCms, driverManager.readPublishList(dbc, job.getPublishHistoryId())); m_publishEngine.unlockPublishList(job); new CmsPublishJobEnqueued(job).m_publishJob.finish(); m_publishEngine.getPublishHistory().add(job); } catch (CmsException exc) { dbc.rollback(); LOG.error(exc.getLocalizedMessage(), exc); } finally { dbc.clear(); } } } } } catch (CmsException exc) { if (LOG.isErrorEnabled()) { LOG.error(exc.getLocalizedMessage(), exc); } } } /** * Checks if the queue is empty.<p> * * @return <code>true</code> if the queue is empty */ protected boolean isEmpty() { return ((OpenCms.getMemoryMonitor() == null) || (OpenCms.getMemoryMonitor().getFirstCachedPublishJob() == null)); } /** * Returns the next publish job to be published, removing it * from the queue, or <code>null</code> if the queue is empty.<p> * * @return the next publish job to be published */ protected CmsPublishJobInfoBean next() { CmsPublishJobInfoBean publishJob = OpenCms.getMemoryMonitor().getFirstCachedPublishJob(); if (publishJob != null) { OpenCms.getMemoryMonitor().uncachePublishJob(publishJob); } return publishJob; } /** * Removes the given job from the list.<p> * * @param publishJob the publish job to remove * * @throws CmsException if something goes wrong */ protected void remove(CmsPublishJobInfoBean publishJob) throws CmsException { try { // signalizes that job will be removed m_publishEngine.publishJobRemoved(publishJob); } finally { // remove publish job from cache OpenCms.getMemoryMonitor().uncachePublishJob(publishJob); } // remove job from database if necessary if (OpenCms.getMemoryMonitor().requiresPersistency()) { CmsDbContext dbc = m_publishEngine.getDbContext(null); try { m_publishEngine.getDriverManager().deletePublishJob(dbc, publishJob.getPublishHistoryId()); } catch (CmsException e) { dbc.rollback(); LOG.error(e.getLocalizedMessage(), e); throw e; } finally { dbc.clear(); } } } /** * Updates the given job in the list.<p> * * @param publishJob the publish job to */ protected void update(CmsPublishJobInfoBean publishJob) { if (OpenCms.getMemoryMonitor().requiresPersistency()) { CmsDbContext dbc = m_publishEngine.getDbContext(null); try { m_publishEngine.getDriverManager().writePublishJob(dbc, publishJob); } catch (CmsException e) { dbc.rollback(); if (LOG.isErrorEnabled()) { LOG.error(e.getLocalizedMessage(), e); } } finally { dbc.clear(); } } } }