org.opencms.cache.CmsMemoryObjectCache Maven / Gradle / Ivy
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/*
* This library is part of OpenCms -
* the Open Source Content Management System
*
* Copyright (c) Alkacon Software GmbH & Co. KG (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 & Co. KG, 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.cache;
import org.opencms.main.CmsEvent;
import org.opencms.main.CmsLog;
import org.opencms.main.I_CmsEventListener;
import org.opencms.main.OpenCms;
import org.opencms.monitor.CmsMemoryMonitor;
import org.apache.commons.logging.Log;
/**
* A singleton memory cache, that stores objects related with keys.
*
* This cache listens to the {@link I_CmsEventListener#EVENT_CLEAR_CACHES} event only.
*
* @since 6.2.3
*/
public final class CmsMemoryObjectCache implements I_CmsEventListener {
/** The log object for this class. */
private static final Log LOG = CmsLog.getLog(CmsMemoryObjectCache.class);
/** A cache that maps VFS resource names to Objects. */
private static CmsMemoryObjectCache m_instance;
/**
* Constructor, creates a new CmsVfsMemoryObjectCache.
*/
private CmsMemoryObjectCache() {
// register the event listeners
registerEventListener();
}
/**
* Returns the singleton memory Object cache instance.
*
* @return the singleton memory Object cache instance
*/
public static CmsMemoryObjectCache getInstance() {
if (m_instance == null) {
m_instance = new CmsMemoryObjectCache();
}
return m_instance;
}
/**
* @see org.opencms.main.I_CmsEventListener#cmsEvent(org.opencms.main.CmsEvent)
*/
public void cmsEvent(CmsEvent event) {
switch (event.getType()) {
case I_CmsEventListener.EVENT_CLEAR_CACHES:
// flush cache
OpenCms.getMemoryMonitor().flushCache(CmsMemoryMonitor.CacheType.MEMORY_OBJECT);
if (LOG.isDebugEnabled()) {
LOG.debug(
org.opencms.xml.Messages.get().getBundle().key(
org.opencms.xml.Messages.LOG_ERR_FLUSHED_CACHES_0));
}
break;
default:
// no operation
}
}
/**
* Returns an object from the cache.
*
* @param owner the owner class of the cached object (used to ensure keys don't overlap)
* @param key the key to lookup the object for
*
* @return an object from the cache, or null if no object matches the given key
*/
public Object getCachedObject(Class owner, String key) {
key = owner.getName().concat(key);
return OpenCms.getMemoryMonitor().getCachedMemObject(key);
}
/**
* Puts an object into the cache.
*
* @param owner the owner class of the cached object (used to ensure keys don't overlap)
* @param key the key to store the object at
* @param value the object to store
*/
public void putCachedObject(Class owner, String key, Object value) {
key = owner.getName().concat(key);
OpenCms.getMemoryMonitor().cacheMemObject(key, value);
}
/**
* Registers all required event listeners.
*/
protected void registerEventListener() {
// register this object as event listener
OpenCms.addCmsEventListener(this, new int[] {I_CmsEventListener.EVENT_CLEAR_CACHES});
}
}