    001// Copyright 2006-2014 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.tapestry5.internal.services;
    016
    017import org.apache.tapestry5.commons.Resource;
    018import org.apache.tapestry5.commons.util.AvailableValues;
    019import org.apache.tapestry5.commons.util.CollectionFactory;
    020import org.apache.tapestry5.commons.util.UnknownValueException;
    021import org.apache.tapestry5.services.AssetAlias;
    022import org.apache.tapestry5.services.ClasspathAssetAliasManager;
    023
    024import java.util.Collections;
    025import java.util.Comparator;
    026import java.util.List;
    027import java.util.Map;
    028
    029public class ClasspathAssetAliasManagerImpl implements ClasspathAssetAliasManager
    030{
    031    /**
    032     * Map from alias to path.
    033     */
    034    private final Map<String, String> aliasToPathPrefix = CollectionFactory.newMap();
    035
    036    /**
    037     * Map from path to alias.
    038     */
    039    private final Map<String, String> pathPrefixToAlias = CollectionFactory.newMap();
    040
    041    private final List<String> sortedPathPrefixes;
    042
    043    /**
    044     * Configuration is a map of aliases (short names) to complete names. Keys and values must not start or end with a slash,
    045     * but may contain them.
    046     */
    047    public ClasspathAssetAliasManagerImpl(Map<String, String> configuration)
    048    {
    049        for (Map.Entry<String, String> e : configuration.entrySet())
    050        {
    051            String alias = verify("folder name", e.getKey());
    052
    053            String path = verify("path", e.getValue());
    054
    055            aliasToPathPrefix.put(alias, path);
    056            pathPrefixToAlias.put(path, alias);
    057        }
    058
    059        Comparator<String> sortDescendingByLength = new Comparator<String>()
    060        {
    061            public int compare(String o1, String o2)
    062            {
    063                return o2.length() - o1.length();
    064            }
    065        };
    066
    067        sortedPathPrefixes = CollectionFactory.newList(aliasToPathPrefix.values());
    068        Collections.sort(sortedPathPrefixes, sortDescendingByLength);
    069    }
    070
    071    private String verify(String name, String input)
    072    {
    073
    074        if (input.startsWith("/") || input.endsWith("/"))
    075            throw new RuntimeException(String.format("Contribution of %s '%s' is invalid as it may not start with or end with a slash.",
    076                    name, input));
    077
    078        return input;
    079
    080    }
    081
    082    public AssetAlias extractAssetAlias(Resource resource)
    083    {
    084        String resourcePath = resource.getPath();
    085
    086        for (String pathPrefix : sortedPathPrefixes)
    087        {
    088            if (resourcePath.startsWith(pathPrefix))
    089            {
    090                if (pathPrefix.length() == resourcePath.length())
    091                {
    092                    throw new IllegalArgumentException(String.format("Resource path '%s' is not valid as it is mapped as virtual folder '%s'.",
    093                            resourcePath,
    094                            pathPrefixToAlias.get(pathPrefix)));
    095                }
    096
    097                // Prevent matching path prefix "foo" against "foobar" ... it must match against "foo/".
    098                if (resourcePath.charAt(pathPrefix.length()) != '/')
    099                {
    100                    continue;
    101                }
    102
    103                String virtualFolder = pathPrefixToAlias.get(pathPrefix);
    104
    105                // Don't want that slash seperating the folder from the rest of the path.
    106                String path = resourcePath.substring(pathPrefix.length() + 1);
    107
    108                return new AssetAlias(virtualFolder, path);
    109            }
    110        }
    111
    112        // This is a minor misuse of the UnknownValueException but the exception reporting
    113        // is too useful to pass up.
    114
    115        throw new UnknownValueException(
    116                String.format(
    117                        "Unable to create a client URL for classpath resource %s: The resource path was not within an aliased path.",
    118                        resourcePath), new AvailableValues("Aliased paths", aliasToPathPrefix.values()));
    119    }
    120
    121    public Map<String, String> getMappings()
    122    {
    123        return Collections.unmodifiableMap(aliasToPathPrefix);
    124    }
    125
    126}