cmstemplatecache.java

cms是开源的框架

/*
* File   : $Source: /usr/local/cvs/opencms/src-modules/com/opencms/template/CmsTemplateCache.java,v $
* Date   : $Date: 2005/06/13 10:00:03 $
* Version: $Revision: 1.4 $
*
* This library is part of OpenCms -
* the Open Source Content Mananagement System
*
* Copyright (C) 2001  The OpenCms Group
*
* 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 OpenCms, please see the
* OpenCms 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 com.opencms.template;

import org.opencms.main.CmsLog;
import org.opencms.main.OpenCms;
import org.opencms.monitor.CmsMemoryMonitor;

import org.apache.commons.collections.map.LRUMap;

/**
 * Implements the OpenCms template cache.<p>
 * 
 * @author Alexander Lucas
 * @version $Revision: 1.4 $ $Date: 2005/06/13 10:00:03 $
 * 
 * @deprecated Will not be supported past the OpenCms 6 release.
 */
public class CmsTemplateCache implements I_CmsTemplateCache {
    
    /** Hashtable to store the cached data. */
    private LRUMap m_templateCache = new LRUMap(1000);
    
    /** 
     * Default constructor to create a template cache.<p>
     */
    public CmsTemplateCache() {
        CmsMemoryMonitor monitor = OpenCms.getMemoryMonitor();
        if ((monitor != null) && monitor.enabled()) {
            monitor.register(this.getClass().getName()+"."+"templateCache", m_templateCache);
        }
        
        if (CmsLog.INIT.isInfoEnabled()) {
            CmsLog.INIT.info(". Loader init          : XMLTemplate template cache initialized successfully");
        }
    }
    
    /** 
     * Deletes all documents from the template cache. 
     */
    public void clearCache() {
        if (CmsLog.getLog(this).isInfoEnabled()) {
            CmsLog.getLog(this).info("Clearing template cache");
        }
        m_templateCache.clear();
    }
    
    /**
     * Deletes the document with the given key from the
     * template cache.
     * @param key Key of the template that should be deleted.
     */
    public void clearCache(Object key) {
        if (key instanceof String) {
            m_templateCache.remove(key);
        } else {
            if (CmsLog.getLog(this).isInfoEnabled()) {
                CmsLog.getLog(this).info("Could not clear key from cache: " + key);
            }
        }
    }
    
    /**
     * Gets a previously cached template with the given key.
     * @param key Key of the requested template.
     * @return byte array with the cached template content or null if no cached value was found.
     */
    public byte[] get(Object key) {
        if (CmsLog.getLog(this).isInfoEnabled()) {
            CmsLog.getLog(this).info("Getting " + key + " from cache");
        }
        if (key instanceof String) {
            return (byte[])m_templateCache.get(key);
        } else {
            if (CmsLog.getLog(this).isInfoEnabled()) {
                CmsLog.getLog(this).info("Getting " + key + " from cache failed");
            }
            return null;
        }
    }
    
    /**
     * Checks if there exists a cached template content for
     * a given key.
     * @param key Key that should be checked.
     * @return <EM>true</EM> if a cached content was found, <EM>false</EM> otherwise.
     */
    public boolean has(Object key) {
        if (key instanceof String) {
            return m_templateCache.get(key) != null;
        } else {
            if (CmsLog.getLog(this).isWarnEnabled()) {
                CmsLog.getLog(this).warn(key + " is not instanceof String");
            }
            return false;
        }
    }
    
    /**
     * Stores a template content in the cache using the given key.
     * @param key Key that should be used to store the template
     * @param content Template content to store.
     */
    public void put(Object key, byte[] content) {
        if (key instanceof String) {
            m_templateCache.put(key, content);
        } else {
            if (CmsLog.getLog(this).isWarnEnabled()) {
                CmsLog.getLog(this).warn(key + " is not instanceof String");
            }
        }
    }
}