001    // Copyright 2004, 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.hivemind.util;
016    
017    import java.net.MalformedURLException;
018    import java.util.Locale;
019    
020    import javax.servlet.ServletContext;
021    
022    /**
023     * Finds localized resources within the web application context.
024     * <p>
025     * Originally part of Tapestry 3.0.
026     * 
027     * @see javax.servlet.ServletContext
028     * @author Howard Lewis Ship
029     * @since 1.1
030     */
031    
032    public class LocalizedContextResourceFinder
033    {
034        private ServletContext _context;
035    
036        public LocalizedContextResourceFinder(ServletContext context)
037        {
038            _context = context;
039        }
040    
041        /**
042         * Resolves the resource, returning a path representing the closest match (with respect to the
043         * provided locale). Returns null if no match.
044         * <p>
045         * The provided path is split into a base path and a suffix (at the last period character). The
046         * locale will provide different suffixes to the base path and the first match is returned.
047         */
048    
049        public LocalizedResource resolve(String contextPath, Locale locale)
050        {
051            int dotx = contextPath.lastIndexOf('.');
052            String basePath;
053            String suffix;
054            if (dotx >= 0) {
055                    basePath = contextPath.substring(0, dotx);
056                    suffix = contextPath.substring(dotx);
057            }
058            else
059            {
060                    // Resource without extension
061                    basePath = contextPath;
062                    suffix = "";
063            }
064    
065            LocalizedNameGenerator generator = new LocalizedNameGenerator(basePath, locale, suffix);
066    
067            while (generator.more())
068            {
069                String candidatePath = generator.next();
070    
071                if (isExistingResource(candidatePath))
072                    return new LocalizedResource(candidatePath, generator.getCurrentLocale());
073            }
074    
075            return null;
076        }
077    
078        private boolean isExistingResource(String path)
079        {
080            try
081            {
082                return _context.getResource(path) != null;
083            }
084            catch (MalformedURLException ex)
085            {
086                return false;
087            }
088        }
089    }