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.frontend.templateone; import org.opencms.i18n.CmsMessages; import org.opencms.jsp.CmsJspActionElement; import org.opencms.main.CmsEvent; import org.opencms.main.CmsLog; import org.opencms.main.I_CmsEventListener; import org.opencms.main.OpenCms; import org.opencms.util.CmsCollectionsGenericWrapper; import org.opencms.util.CmsUUID; import java.util.Collections; import java.util.Locale; import java.util.Map; import org.apache.commons.logging.Log; /** * Stores static Strings to generate HTML output parts for the template in a Map.<p> * * An instance of this class is stored in the OpenCms runtime properties.<p> * * @since 6.0.0 */ public final class CmsTemplateParts implements I_CmsEventListener { /** Key name for an illegal key. */ public static final String KEY_ILLEGAL = "illpart"; /** The log object for this class. */ private static final Log LOG = CmsLog.getLog(CmsTemplateParts.class); /** The Singleton instance. */ private static CmsTemplateParts m_instance; /** The internal map of cached template parts. */ private Map m_parts; /** * Hidden constructor.<p> * * Use the getInstance(CmsJspActionElement) method to get an initialized instance of this class.<p> */ private CmsTemplateParts() { // create new Map initPartsMap(); // add an event listener OpenCms.addCmsEventListener(this); } /** * Returns an instance of the class fetched from the application context attribute.<p> * * @return an instance of the class */ public static CmsTemplateParts getInstance() { if (m_instance == null) { // initialize the Singleton instance m_instance = new CmsTemplateParts(); } return m_instance; } /** * Sets a part in the cache with the specified key and value.<p> * * @param partKey the key to identify the part * @param value the value to cache */ public void addPart(String partKey, String value) { if (!partKey.equals(KEY_ILLEGAL)) { // only store part if valid part key was found m_parts.put(partKey, value); } } /** * Implements the CmsEvent interface, clears the template parts on publish and clear cache events.<p> * * @param event CmsEvent that has occurred */ public void cmsEvent(CmsEvent event) { switch (event.getType()) { case I_CmsEventListener.EVENT_PUBLISH_PROJECT: case I_CmsEventListener.EVENT_CLEAR_CACHES: case I_CmsEventListener.EVENT_FLEX_CACHE_CLEAR: case I_CmsEventListener.EVENT_FLEX_PURGE_JSP_REPOSITORY: // flush Map initPartsMap(); if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_CMSTEMPLATEPARTS_CLEARED_0)); } break; default: // no operation } } /** * Returns a previously cached part of template one with the specified key, or null, if no part is found.<p> * * @param partKey the key to identify the part * @return a previously cached part of template one with the specified key */ public String getPart(String partKey) { return (String) m_parts.get(partKey); } /** * Returns the content of the specified JSP target file depending on the element and the layout to display.<p> * * @param target the target uri of the file in the OpenCms VFS (can be relative or absolute) * @param element the element (template selector) to display from the target * @param layout the layout type of the template to get * @param jsp the JSP page to generate the content with * * @return the content of the JSP target file */ public String includePart(String target, String element, String layout, CmsJspActionElement jsp) { if (OpenCms.getRunLevel() < OpenCms.RUNLEVEL_4_SERVLET_ACCESS) { // OpenCms is not in servlet based operating mode, return empty String return ""; } String part = null; String partKey = ""; try { // generate a unique key for the included part partKey = generateKey(target, element, layout, jsp.getRequestContext().getLocale(), jsp.getRequestContext().getCurrentProject().getUuid()); // try to get the part part = (String) m_parts.get(partKey); if (part == null) { // part not found, get the content of the JSP element and put it to the Map store part = jsp.getContent(target, element, jsp.getRequestContext().getLocale()); if ((part != null) && !part.startsWith(CmsMessages.UNKNOWN_KEY_EXTENSION)) { // add part to map if a valid content was found addPart(partKey, part); } else { // prevent displaying rubbish part = ""; } if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_INCLUDE_PART_NOT_FOUND_1, partKey)); } } else if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_INCLUDE_PART_FOUND_1, partKey)); } } catch (Throwable t) { // catch all errors to avoid displaying rubbish part = ""; if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_INCLUDE_PART_ERR_2, partKey, t)); } } return part; } /** * Generates a part key depending on the included target, the element and the layout do display.<p> * * @param target the target uri of the file in the OpenCms VFS (can be relative or absolute) * @param element the element (template selector) to display from the target * @param layout the layout type of the template to get * @param locale the locale to use * @param project the project id * * @return a unique part key */ private String generateKey(String target, String element, String layout, Locale locale, CmsUUID project) { try { if (element == null) { // set element name to empty String for key generation element = ""; } // generate the key to identify the current part StringBuffer partKey = new StringBuffer(32); partKey.append(target); partKey.append("_"); partKey.append(element); partKey.append("_"); partKey.append(layout); partKey.append("_"); partKey.append(locale); partKey.append("_"); partKey.append(project); return partKey.toString(); } catch (Exception e) { // error creating key return KEY_ILLEGAL; } } /** * Initializes (also clears) the internal part cache map.<p> * * @return the new created part cache map */ private synchronized Map initPartsMap() { Map cacheParts = CmsCollectionsGenericWrapper.createLRUMap(512); Map oldParts = m_parts; m_parts = Collections.synchronizedMap(cacheParts); if (oldParts != null) { oldParts.clear(); oldParts = null; } return m_parts; } }