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.hivemind.util;
016
017import java.net.MalformedURLException;
018import java.util.Locale;
019
020import 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
032public 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}