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
015package org.apache.tapestry.web;
016
017import java.util.Locale;
018
019import org.apache.hivemind.util.LocalizedNameGenerator;
020import 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
029public 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}