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.tapestry.web;
016    
017    import java.util.Locale;
018    
019    import org.apache.hivemind.util.LocalizedNameGenerator;
020    import org.apache.hivemind.util.LocalizedResource;
021    
022    /**
023     * Finds localized resources within a {@link org.apache.tapestry.web.WebContext}..
024     * 
025     * @author Howard Lewis Ship
026     * @since 4.0
027     */
028    
029    public class LocalizedWebContextResourceFinder
030    {
031        private WebContext _context;
032    
033        public LocalizedWebContextResourceFinder(WebContext context)
034        {
035            _context = context;
036        }
037    
038        /**
039         * Resolves the resource, returning a path representing the closest match (with respect to the
040         * provided locale). Returns null if no match.
041         * <p>
042         * The provided path is split into a base path and a suffix (at the last period character). The
043         * locale will provide different suffixes to the base path and the first match is returned.
044         */
045    
046        public LocalizedResource resolve(String contextPath, Locale locale)
047        {
048            int dotx = contextPath.lastIndexOf('.');
049            String basePath;
050            String suffix;
051            if (dotx >= 0) {
052                    basePath = contextPath.substring(0, dotx);
053                    suffix = contextPath.substring(dotx);
054            }
055            else
056            {
057                    // Resource without extension
058                    basePath = contextPath;
059                    suffix = "";
060            }
061    
062            LocalizedNameGenerator generator = new LocalizedNameGenerator(basePath, locale, suffix);
063    
064            while (generator.more())
065            {
066                String candidatePath = generator.next();
067    
068                if (isExistingResource(candidatePath))
069                    return new LocalizedResource(candidatePath, generator.getCurrentLocale());
070            }
071    
072            return null;
073        }
074    
075        private boolean isExistingResource(String path)
076        {
077            return _context.getResource(path) != null;
078        }
079    }