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, 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.search.documents; import org.opencms.cache.CmsVfsDiskCache; import org.opencms.file.CmsResource; import org.opencms.main.CmsLog; import org.opencms.search.extractors.CmsExtractionResult; import org.opencms.search.extractors.I_CmsExtractionResult; import org.opencms.util.CmsFileUtil; import java.io.File; import java.io.IOException; import java.util.Locale; import org.apache.commons.logging.Log; /** * Implements a disk cache that stores text extraction results in the RFS.<p> * * This cache operates on resource file names, plus a hash code calculated from * {@link org.opencms.file.CmsResource#getDateLastModified()} * and {@link org.opencms.file.CmsResource#getLength()}. Optional a locale can be appended to this name.<p> * * Since text extraction is done only on the content of a resource, all siblings must have the same content. * The difference can be only by the locale setting in case of an XML content or XML page. However, * the most problematic contents to extract for the search are in fact the MS Office and PDF formats. * For these documents, all siblings must produce the exact same text extraction result.<p> * * This cache is usable for resources from the online AND the offline project at the same time, * because any change to a resource will result in a changed hash code. This means a resource changed in the offline * project will have a new hash code compared to the online project. If the resource is identical in the online and * the offline project, the generated hash codes will be the same.<p> * * @since 6.2.0 */ public class CmsExtractionResultCache { /** The log object for this class. */ private static final Log LOG = CmsLog.getLog(CmsExtractionResultCache.class); /** The name of the cache base repository folder in the RFS. */ private String m_rfsRepository; /** * Creates a new disk cache.<p> * * @param basepath the base path for the cache in the RFS * @param foldername the folder name for this cache, to be used a subfolder for the base folder */ public CmsExtractionResultCache(String basepath, String foldername) { // normalize the given folder name m_rfsRepository = CmsFileUtil.normalizePath(basepath + foldername + File.separatorChar); } /** * Removes all expired extraction result cache entries from the RFS cache.<p> * * @param maxAge the maximum age of the extraction result cache files in hours (or fractions of hours) * * @return the total number of deleted resources */ public synchronized int cleanCache(float maxAge) { // calculate oldest possible date for the cache files long expireDate = System.currentTimeMillis() - (long) (maxAge * 60.0f * 60.0f * 1000.0f); File basedir = new File(m_rfsRepository); // perform the cache cleanup int count = 0; if (basedir.canRead() && basedir.isDirectory()) { File[] files = basedir.listFiles(); if (files != null) { for (int i = 0; i < files.length; i++) { File f = files[i]; if (f.canWrite()) { if (f.lastModified() < expireDate) { try { f.delete(); count++; } catch (Exception e) { if (LOG.isWarnEnabled()) { LOG.warn( Messages.get().getBundle().key( Messages.LOG_EXCERPT_CACHE_DELETE_ERROR_1, f.getAbsolutePath()), e); } } } } } } } return count; } /** * Returns the RFS name used for caching an the text extraction result * based on the given VFS resource and locale.<p> * * @param resource the VFS resource to generate the cache name for * @param locale the locale to generate the cache name for (may be <code>null</code>) * * @return the RFS name to use for caching the given VFS resource with parameters */ public String getCacheName(CmsResource resource, Locale locale) { // create a StringBuffer for the result StringBuffer buf = new StringBuffer(m_rfsRepository.length() + 36); buf.append(m_rfsRepository); buf.append('/'); buf.append(resource.getResourceId().toString()); // check if parameters are provided, if so add them as well if (locale != null) { buf.append('_'); buf.append(locale.toString()); } // append the date of last content modification to the result buffer // please note that we need only worry about last change in content, since properties are ignored here buf.append('_'); buf.append(resource.getDateContent()); // finally append the extension buf.append(".ext"); return buf.toString(); } /** * Returns the extraction result in the requested file in the disk cache, or <code>null</code> if the * file is not found in the cache, or is found but out-dated.<p> * * @param rfsName the file RFS name to look up in the cache * * @return the extraction result stored in the requested file in the RFS disk cache, or <code>null</code> */ public CmsExtractionResult getCacheObject(String rfsName) { try { File f = new File(rfsName); if (f.exists()) { long age = f.lastModified(); if ((System.currentTimeMillis() - age) > 3600000) { // file has not been touched for 1 hour, touch the file with the current date f.setLastModified(System.currentTimeMillis()); } byte[] byteContent = CmsFileUtil.readFile(f); return CmsExtractionResult.fromBytes(byteContent); } } catch (IOException e) { // unable to read content } // this code can be reached only in case of an error return null; } /** * Returns the absolute path of the cache repository in the RFS.<p> * * @return the absolute path of the cache repository in the RFS */ public String getRepositoryPath() { return m_rfsRepository; } /** * Serializes the given extraction result and saves it in the disk cache.<p> * * @param rfsName the RFS name of the file to save the extraction result in * @param content the extraction result to serialize and save * * @throws IOException in case of disk access errors */ public void saveCacheObject(String rfsName, I_CmsExtractionResult content) throws IOException { byte[] byteContent = content.getBytes(); if (byteContent != null) { CmsVfsDiskCache.saveFile(rfsName, byteContent); } } }