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.configuration; import org.opencms.i18n.CmsEncoder; import org.opencms.main.CmsLog; import org.opencms.util.CmsFileUtil; import org.opencms.xml.CmsXmlEntityResolver; import org.opencms.xml.CmsXmlErrorHandler; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import java.net.URL; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Date; import java.util.Iterator; import java.util.List; import org.apache.commons.digester.Digester; import org.apache.commons.logging.Log; import org.dom4j.Document; import org.dom4j.DocumentHelper; import org.dom4j.Element; import org.dom4j.dom.DOMDocumentType; import org.dom4j.io.OutputFormat; import org.dom4j.io.XMLWriter; import org.xml.sax.SAXException; /** * Configuration manager for digesting the OpenCms XML configuration.<p> * * Reads the individual configuration class nodes first and creaes new * instances of the "base" configuration classes.<p> * * @since 6.0.0 */ public class CmsConfigurationManager implements I_CmsXmlConfiguration { /** The location of the OpenCms configuration DTD if the default prefix is the system ID. */ public static final String DEFAULT_DTD_LOCATION = "org/opencms/configuration/"; /** The default prefix for the OpenCms configuration DTD. */ public static final String DEFAULT_DTD_PREFIX = "http://www.opencms.org/dtd/6.0/"; /** The name of the default XML file for this configuration. */ public static final String DEFAULT_XML_FILE_NAME = "opencms.xml"; /** The name of the DTD file for this configuration. */ public static final String DTD_FILE_NAME = "opencms-configuration.dtd"; /** The "opencms" root node of the XML configuration. */ public static final String N_ROOT = "opencms"; /** Postfix for original configuration files. */ public static final String POSTFIX_ORI = ".ori"; /** The config node. */ protected static final String N_CONFIG = "config"; /** The configurations node. */ protected static final String N_CONFIGURATION = "configuration"; /** Date format for the backup file time prefix. */ private static final SimpleDateFormat BACKUP_DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd_HH-mm-ss_"); /** The log object for this class. */ private static final Log LOG = CmsLog.getLog(CmsConfigurationManager.class); /** The number of days to keep old backups for. */ private static final long MAX_BACKUP_DAYS = 15; /** The folder where to store the backup files of the configuration. */ private File m_backupFolder; /** The base folder where the configuration files are located. */ private File m_baseFolder; /** The initialized configuration classes. */ private List<I_CmsXmlConfiguration> m_configurations; /** The digester for reading the XML configuration. */ private Digester m_digester; /** The configuration based on <code>opencms.properties</code>. */ private CmsParameterConfiguration m_propertyConfiguration; /** * Creates a new OpenCms configuration manager.<p> * * @param baseFolder base folder where XML configurations to load are located */ public CmsConfigurationManager(String baseFolder) { m_baseFolder = new File(baseFolder); if (!m_baseFolder.exists()) { if (LOG.isErrorEnabled()) { LOG.error(Messages.get().getBundle().key(Messages.LOG_INVALID_CONFIG_BASE_FOLDER_1, m_baseFolder.getAbsolutePath())); } } m_backupFolder = new File(m_baseFolder.getAbsolutePath() + File.separatorChar + "backup"); if (!m_backupFolder.exists()) { if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_CREATE_CONFIG_BKP_FOLDER_1, m_backupFolder.getAbsolutePath())); } m_backupFolder.mkdirs(); } if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_CONFIG_BASE_FOLDER_1, m_baseFolder.getAbsolutePath())); LOG.debug(Messages.get().getBundle().key(Messages.LOG_CONFIG_BKP_FOLDER_1, m_backupFolder.getAbsolutePath())); } cacheDtdSystemId(this); m_configurations = new ArrayList<I_CmsXmlConfiguration>(); } /** * Adds a configuration object to the configuration manager.<p> * * @param configuration the configuration to add */ public void addConfiguration(I_CmsXmlConfiguration configuration) { if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_ADD_CONFIG_1, configuration)); } m_configurations.add(configuration); cacheDtdSystemId(configuration); } /** * @see org.opencms.configuration.I_CmsConfigurationParameterHandler#addConfigurationParameter(java.lang.String, java.lang.String) */ public void addConfigurationParameter(String paramName, String paramValue) { // noop, this configuration has no additional parameters } /** * @see org.opencms.configuration.I_CmsXmlConfiguration#addXmlDigesterRules(org.apache.commons.digester.Digester) */ public void addXmlDigesterRules(Digester digester) { // add rule for <configuration> node digester.addObjectCreate("*/" + N_CONFIGURATION + "/" + N_CONFIG, I_CmsXmlConfiguration.A_CLASS, CmsConfigurationException.class); digester.addSetNext("*/" + N_CONFIGURATION + "/" + N_CONFIG, "addConfiguration"); } /** * @see org.opencms.configuration.I_CmsXmlConfiguration#generateXml(org.dom4j.Element) */ public Element generateXml(Element parent) { // add the <configuration> node Element configurationElement = parent.addElement(N_CONFIGURATION); for (int i = 0; i < m_configurations.size(); i++) { // append the individual configuration I_CmsXmlConfiguration configuration = m_configurations.get(i); configurationElement.addElement(N_CONFIG).addAttribute(I_CmsXmlConfiguration.A_CLASS, configuration.getClass().getName()); } return parent; } /** * Creates the XML document build from the provided configuration.<p> * * @param configuration the configuration to build the XML for * @return the XML document build from the provided configuration */ public Document generateXml(I_CmsXmlConfiguration configuration) { // create a new document Document result = DocumentHelper.createDocument(); // set the document type DOMDocumentType docType = new DOMDocumentType(); docType.setElementName(N_ROOT); docType.setSystemID(configuration.getDtdUrlPrefix() + configuration.getDtdFilename()); result.setDocType(docType); Element root = result.addElement(N_ROOT); // start the XML generation configuration.generateXml(root); // return the resulting document return result; } /** * Returns the backup folder.<p> * * @return the backup folder */ public File getBackupFolder() { return m_backupFolder; } /** * Returns the properties read from <code>opencms.properties</code>.<p> * * @see #setConfiguration(CmsParameterConfiguration) * @see org.opencms.configuration.I_CmsConfigurationParameterHandler#getConfiguration() */ public CmsParameterConfiguration getConfiguration() { return m_propertyConfiguration; } /** * Returns a specific configuration from the list of initialized configurations.<p> * * @param clazz the configuration class that should be returned * @return the initialized configuration class instance, or <code>null</code> if this is not found */ public I_CmsXmlConfiguration getConfiguration(Class<?> clazz) { for (int i = 0; i < m_configurations.size(); i++) { I_CmsXmlConfiguration configuration = m_configurations.get(i); if (clazz.equals(configuration.getClass())) { return configuration; } } return null; } /** * Returns the list of all initialized configurations.<p> * * @return the list of all initialized configurations */ public List<I_CmsXmlConfiguration> getConfigurations() { return m_configurations; } /** * @see org.opencms.configuration.I_CmsXmlConfiguration#getDtdFilename() */ public String getDtdFilename() { return DTD_FILE_NAME; } /** * @see org.opencms.configuration.I_CmsXmlConfiguration#getDtdSystemLocation() */ public String getDtdSystemLocation() { return DEFAULT_DTD_LOCATION; } /** * @see org.opencms.configuration.I_CmsXmlConfiguration#getDtdUrlPrefix() */ public String getDtdUrlPrefix() { return DEFAULT_DTD_PREFIX; } /** * @see org.opencms.configuration.I_CmsXmlConfiguration#getXmlFileName() */ public String getXmlFileName() { return DEFAULT_XML_FILE_NAME; } /** * @see org.opencms.configuration.I_CmsConfigurationParameterHandler#initConfiguration() */ public void initConfiguration() { // does not need to be initialized if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_INIT_CONFIGURATION_1, this)); } } /** * Loads the OpenCms configuration from the given XML file.<p> * * @throws SAXException in case of XML parse errors * @throws IOException in case of file IO errors */ public void loadXmlConfiguration() throws SAXException, IOException { URL baseUrl = m_baseFolder.toURI().toURL(); if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_BASE_URL_1, baseUrl)); } // first load the base configuration loadXmlConfiguration(baseUrl, this); // now iterate all sub-configurations Iterator<I_CmsXmlConfiguration> i = m_configurations.iterator(); while (i.hasNext()) { loadXmlConfiguration(baseUrl, i.next()); } // remove the old backups removeOldBackups(MAX_BACKUP_DAYS); } /** * Sets the configuration read from the <code>opencms.properties</code>.<p> * * @param propertyConfiguration the configuration read from the <code>opencms.properties</code> * * @see #getConfiguration() */ public void setConfiguration(CmsParameterConfiguration propertyConfiguration) { m_propertyConfiguration = propertyConfiguration; } /** * Writes the XML configuration for the provided configuration instance.<p> * * @param clazz the configuration class to write the XML for * @throws IOException in case of I/O errors while writing * @throws CmsConfigurationException if the given class is not a valid configuration class */ public void writeConfiguration(Class<?> clazz) throws IOException, CmsConfigurationException { I_CmsXmlConfiguration configuration = getConfiguration(clazz); if (configuration == null) { throw new CmsConfigurationException( Messages.get().container(Messages.ERR_CONFIG_WITH_UNKNOWN_CLASS_1, clazz.getName())); } // generate the file URL for the XML input File file = new File(m_baseFolder, configuration.getXmlFileName()); if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_WRITE_CONFIG_XMLFILE_1, file.getAbsolutePath())); } // generate the XML document Document config = generateXml(configuration); // output the document XMLWriter writer = null; OutputFormat format = OutputFormat.createPrettyPrint(); format.setIndentSize(4); format.setTrimText(false); format.setEncoding(CmsEncoder.ENCODING_UTF_8); try { OutputStream out = new FileOutputStream(file); writer = new XMLWriter(out, format); writer.write(config); writer.flush(); } finally { if (writer != null) { writer.close(); } } if (LOG.isInfoEnabled()) { LOG.info(Messages.get().getBundle().key(Messages.LOG_WRITE_CONFIG_SUCCESS_2, file.getAbsolutePath(), configuration.getClass().getName())); } } /** * Creates a backup of the given XML configurations input file.<p> * * @param configuration the configuration for which the input file should be backed up */ private void backupXmlConfiguration(I_CmsXmlConfiguration configuration) { String fromName = m_baseFolder.getAbsolutePath() + File.separatorChar + configuration.getXmlFileName(); String toDatePrefix = BACKUP_DATE_FORMAT.format(new Date()); String toName = m_backupFolder.getAbsolutePath() + File.separatorChar + toDatePrefix + configuration.getXmlFileName(); if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_CREATE_CONFIG_BKP_2, fromName, toName)); } try { CmsFileUtil.copy(fromName, toName); } catch (IOException e) { LOG.error(Messages.get().getBundle().key(Messages.LOG_CREATE_CONFIG_BKP_FAILURE_1, toName), e); } } /** * Adds a new DTD system id prefix mapping for internal resolution of external URLs.<p> * * @param configuration the configuration to add the mapping from */ private void cacheDtdSystemId(I_CmsXmlConfiguration configuration) { if (configuration.getDtdSystemLocation() != null) { try { String file = CmsFileUtil.readFile( configuration.getDtdSystemLocation() + configuration.getDtdFilename(), CmsEncoder.ENCODING_UTF_8); CmsXmlEntityResolver.cacheSystemId(configuration.getDtdUrlPrefix() + configuration.getDtdFilename(), file.getBytes(CmsEncoder.ENCODING_UTF_8)); if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_CACHE_DTD_SYSTEM_ID_1, configuration.getDtdUrlPrefix() + configuration.getDtdFilename() + " --> " + configuration.getDtdSystemLocation() + configuration.getDtdFilename())); } } catch (IOException e) { LOG.error(Messages.get().getBundle().key(Messages.LOG_CACHE_DTD_SYSTEM_ID_FAILURE_1, configuration.getDtdSystemLocation() + configuration.getDtdFilename()), e); } } } /** * Loads the OpenCms configuration from the given XML URL.<p> * * @param url the base URL of the XML configuration to load * @param configuration the configuration to load * @throws SAXException in case of XML parse errors * @throws IOException in case of file IO errors */ private void loadXmlConfiguration(URL url, I_CmsXmlConfiguration configuration) throws SAXException, IOException { // generate the file URL for the XML input URL fileUrl = new URL(url, configuration.getXmlFileName()); if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_LOAD_CONFIG_XMLFILE_1, fileUrl)); } // create a backup of the configuration backupXmlConfiguration(configuration); // instantiate Digester and enable XML validation m_digester = new Digester(); m_digester.setUseContextClassLoader(true); m_digester.setValidating(true); m_digester.setEntityResolver(new CmsXmlEntityResolver(null)); m_digester.setRuleNamespaceURI(null); m_digester.setErrorHandler(new CmsXmlErrorHandler(fileUrl.getFile())); // add this class to the Digester m_digester.push(configuration); configuration.addXmlDigesterRules(m_digester); // start the parsing process m_digester.parse(fileUrl.openStream()); } /** * Removes all backups that are older then the given number of days.<p> * * @param daysToKeep the days to keep the backups for */ private void removeOldBackups(long daysToKeep) { long maxAge = (System.currentTimeMillis() - (daysToKeep * 24 * 60 * 60 * 1000)); File[] files = m_backupFolder.listFiles(); for (int i = 0; i < files.length; i++) { File file = files[i]; long lastMod = file.lastModified(); if ((lastMod < maxAge) & (!file.getAbsolutePath().endsWith(CmsConfigurationManager.POSTFIX_ORI))) { file.delete(); if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.LOG_REMOVE_CONFIG_FILE_1, file.getAbsolutePath())); } } } } }