cmslocalemanager.java

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/*
 * File   : $Source: /usr/local/cvs/opencms/src/org/opencms/i18n/CmsLocaleManager.java,v $
 * Date   : $Date: 2007-08-29 16:22:22 $
 * Version: $Revision: 1.55 $
 *
 * This library is part of OpenCms -
 * the Open Source Content Management System
 *
 * Copyright (c) 2002 - 2007 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.i18n;

import org.opencms.file.CmsObject;
import org.opencms.file.CmsProject;
import org.opencms.file.CmsPropertyDefinition;
import org.opencms.file.CmsResource;
import org.opencms.file.CmsUser;
import org.opencms.main.CmsEvent;
import org.opencms.main.CmsException;
import org.opencms.main.CmsLog;
import org.opencms.main.I_CmsEventListener;
import org.opencms.main.OpenCms;
import org.opencms.util.CmsStringUtil;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.logging.Log;

/**
 * Manages the locales configured for this OpenCms installation.<p>
 * 
 * Locale configuration is done in the configuration file <code>opencms-system.xml</code>
 * in the <code>opencms/system/internationalization</code> node and it's sub-nodes.<p>
 * 
 * @author Carsten Weinholz 
 * @author Alexander Kandzior 
 * 
 * @version $Revision: 1.55 $ 
 * 
 * @since 6.0.0 
 */
public class CmsLocaleManager implements I_CmsEventListener {

    /** Runtime property name for locale handler. */
    public static final String LOCALE_HANDLER = "class_locale_handler";

    /** Request parameter to force encoding selection. */
    public static final String PARAMETER_ENCODING = "__encoding";

    /** Request parameter to force locale selection. */
    public static final String PARAMETER_LOCALE = "__locale";

    /** The log object for this class. */
    private static final Log LOG = CmsLog.getLog(CmsLocaleManager.class);

    /** The default locale, this is the first configured locale. */
    private static Locale m_defaultLocale;

    /** The set of available locale names. */
    private List m_availableLocales;

    /** The default locale names (must be a subset of the available locale names). */
    private List m_defaultLocales;

    /** Indicates if the locale manager is fully initialized. */
    private boolean m_initialized;

    /** The configured locale handler. */
    private I_CmsLocaleHandler m_localeHandler;

    /**
     * Initializes a new CmsLocaleManager, called from the configuration.<p>
     */
    public CmsLocaleManager() {

        setDefaultLocale();
        m_availableLocales = new ArrayList();
        m_defaultLocales = new ArrayList();
        m_localeHandler = new CmsDefaultLocaleHandler();
        if (CmsLog.INIT.isInfoEnabled()) {
            CmsLog.INIT.info(Messages.get().getBundle().key(Messages.INIT_I18N_CONFIG_START_0));
        }
        // register this object as event listener
        OpenCms.addCmsEventListener(this, new int[] {I_CmsEventListener.EVENT_CLEAR_CACHES});
    }

    /**
     * Initializes a new CmsLocaleManager, used for OpenCms runlevel 1 (unit tests) only.<p>
     * 
     * @param defaultLocale the default locale to use
     */
    public CmsLocaleManager(Locale defaultLocale) {

        setDefaultLocale();
        m_initialized = false;

        m_availableLocales = new ArrayList();
        m_defaultLocales = new ArrayList();
        m_localeHandler = new CmsDefaultLocaleHandler();

        m_defaultLocale = defaultLocale;
        m_defaultLocales.add(defaultLocale);
        m_availableLocales.add(defaultLocale);
    }

    /**
     * Required for setting the default locale on the first possible time.<p>
     */
    static {
        setDefaultLocale();
    }

    /**
     * Returns the default locale configured in <code>opencms-system.xml</code>, 
     * that is the first locale from the list provided
     * in the <code>opencms/system/internationalization/localesdefault</code> node.<p>
     *
     * @return the default locale configured in <code>opencms-system.xml</code>
     */
    public static Locale getDefaultLocale() {

        return m_defaultLocale;
    }

    /**
     * Returns a locale created from the given full name.<p>
     * 
     * The full name must consist of language code, 
     * country code(optional), variant(optional) separated by "_".<p>
     * 
     * This method will always return a valid Locale!
     * If the provided locale name is not valid (i.e. leads to an Exception
     * when trying to create the Locale, then the configured default Locale is returned.<p> 
     * 
     * @param localeName the full locale name
     * @return the locale or <code>null</code> if not available
     */
    public static Locale getLocale(String localeName) {

        if (CmsStringUtil.isEmpty(localeName)) {
            return getDefaultLocale();
        }
        Locale locale = null;
        if (OpenCms.getMemoryMonitor() != null) {
            // this may be used AFTER shutdown
            locale = OpenCms.getMemoryMonitor().getCachedLocale(localeName);
        }
        if (locale != null) {
            return locale;
        }
        try {
            String[] localeNames = CmsStringUtil.splitAsArray(localeName, '_');
            locale = new Locale(
                localeNames[0],
                (localeNames.length > 1) ? localeNames[1] : "",
                (localeNames.length > 2) ? localeNames[2] : "");
        } catch (Throwable t) {
            LOG.debug(Messages.get().getBundle().key(Messages.LOG_CREATE_LOCALE_FAILED_1, localeName), t);
            // map this error to the default locale
            locale = getDefaultLocale();
        }
        if (OpenCms.getMemoryMonitor() != null) {
            // this may be used AFTER shutdown
            OpenCms.getMemoryMonitor().cacheLocale(localeName, locale);
        }
        return locale;
    }

    /**
     * Returns the locale names from the given List of locales as a comma separated String.<p>
     * 
     * For example, if the input List contains <code>{@link Locale#ENGLISH}</code> and 
     * <code>{@link Locale#GERMANY}</code>, the result will be <code>"en, de_DE"</code>.<p>
     * 
     * An empty String is returned if the input is <code>null</code>, or contains no elements.<p>
     * 
     * @param localeNames the locale names to generate a String from
     * 
     * @return the locale names from the given List of locales as a comma separated String
     */
    public static String getLocaleNames(List localeNames) {

        StringBuffer result = new StringBuffer();
        if (localeNames != null) {
            Iterator i = localeNames.iterator();
            while (i.hasNext()) {
                result.append(i.next().toString());
                if (i.hasNext()) {
                    result.append(", ");
                }
            }
        }
        return result.toString();
    }

    /**
     * Returns a List of locales from an array of locale names.<p>
     * 
     * @param localeNames array of locale names
     * @return a List of locales derived from the given locale names
     */
    public static List getLocales(List localeNames) {

        List result = new ArrayList(localeNames.size());
        for (int i = 0; i < localeNames.size(); i++) {
            result.add(getLocale(localeNames.get(i).toString().trim()));
        }
        return result;
    }

    /**
     * Returns a List of locales from a comma-separated string of locale names.<p>
     * 
     * @param localeNames a comma-separated string of locale names
     * @return a List of locales derived from the given locale names
     */
    public static List getLocales(String localeNames) {

        if (localeNames == null) {
            return null;
        }
        return getLocales(CmsStringUtil.splitAsList(localeNames, ','));
    }

    /**
     * Returns the content encoding set for the given resource.<p>
     * 
     * The content encoding is controlled by the property {@link CmsPropertyDefinition#PROPERTY_CONTENT_ENCODING},
     * which can be set on the resource or on a parent folder for all resources in this folder.<p>
     * 
     * In case no encoding has been set, the default encoding from 
     * {@link org.opencms.main.CmsSystemInfo#getDefaultEncoding()} is returned.<p> 
     * 
     * @param cms the current OpenCms user context
     * @param res the resource to read the encoding for
     * 
     * @return the content encoding set for the given resource
     */
    public static final String getResourceEncoding(CmsObject cms, CmsResource res) {

        String encoding = null;
        // get the encoding
        try {
            encoding = cms.readPropertyObject(res, CmsPropertyDefinition.PROPERTY_CONTENT_ENCODING, true).getValue();
            if (encoding != null) {
                encoding = CmsEncoder.lookupEncoding(encoding.trim(), encoding);
            }
        } catch (CmsException e) {
            if (LOG.isInfoEnabled()) {
                LOG.info(Messages.get().getBundle().key(Messages.ERR_READ_ENCODING_PROP_1, res.getRootPath()), e);
            }
        }
        if (encoding == null) {
            encoding = OpenCms.getSystemInfo().getDefaultEncoding();
        }
        return encoding;
    }

    /**
     * Sets the default locale of the Java VM to <code>{@link Locale#ENGLISH}</code> if the 
     * current default has any other language then English set.<p>
     *
     * This is required because otherwise the default (English) resource bundles 
     * would not be displayed for the English locale if a translated default locale exists.<p>
     * 
     * Here's an example of how this issues shows up:
     * On a German server, the default locale usually is <code>{@link Locale#GERMAN}</code>.
     * All English translations for OpenCms are located in the "default" message files, for example 
     * <code>org.opencms.i18n.message.properties</code>. If the German localization is installed, it will be
     * located in <code>org.opencms.i18n.message_de.properties</code>. If user has English selected
     * as his locale, the default Java lookup mechanism first tries to find 
     * <code>org.opencms.i18n.message_en.properties</code>. However, this file does not exist, since the
     * English localization is kept in the default file. Next, the Java lookup mechanism tries to find the servers
     * default locale, which in this example is German. Since there is a German message file, the Java lookup mechanism
     * is finished and uses this German localization, not the default file. Therefore the 
     * user get the German localization, not the English one.
     * Setting the default locale explicitly to English avoids this issue.<p>
     */
    private static void setDefaultLocale() {

        // set the default locale to english
        // this is required because otherwise the default (english) resource bundles 
        // would not be displayed for the english locale if a translated locale exists