001/*
002 *  Copyright 2012 Anyware Services
003 *
004 *  Licensed under the Apache License, Version 2.0 (the "License");
005 *  you may not use this file except in compliance with the License.
006 *  You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 *  Unless required by applicable law or agreed to in writing, software
011 *  distributed under the License is distributed on an "AS IS" BASIS,
012 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 *  See the License for the specific language governing permissions and
014 *  limitations under the License.
015 */
016package org.ametys.runtime.plugin;
017
018import java.io.File;
019import java.io.IOException;
020import java.net.MalformedURLException;
021import java.util.Map;
022import java.util.regex.Matcher;
023import java.util.regex.Pattern;
024
025import org.apache.avalon.framework.logger.AbstractLogEnabled;
026import org.apache.avalon.framework.service.ServiceException;
027import org.apache.avalon.framework.service.ServiceManager;
028import org.apache.avalon.framework.service.Serviceable;
029import org.apache.excalibur.source.Source;
030import org.apache.excalibur.source.SourceFactory;
031import org.apache.excalibur.source.SourceNotFoundException;
032import org.apache.excalibur.source.SourceResolver;
033import org.apache.excalibur.source.impl.FileSource;
034
035import org.ametys.core.source.OptionalSourceFallbackExtensionPoint;
036
037
038/**
039 * SourceFactory handling resources URIs for plugins.
040 * Plugin resources can be found of File System, in a JAR, ...
041 */
042public class PluginSourceFactory extends AbstractLogEnabled implements SourceFactory, Serviceable
043{
044    private static final Pattern __SOURCE_PATTERN = Pattern.compile("^[\\w]+:(" + PluginsManager.PLUGIN_NAME_REGEXP + ")(\\?)?://(.*)$");
045    
046    private SourceResolver _resolver;
047
048    private OptionalSourceFallbackExtensionPoint _optionalSourceFallbackExtensionPoint;
049
050    private ServiceManager _manager;
051    
052    public Source getSource(String location, Map parameters) throws IOException
053    {
054        Matcher m = __SOURCE_PATTERN.matcher(location);
055        if (!m.matches())
056        {
057            throw new MalformedURLException("URI must be like protocol:<plugin name>://path/to/resource. Location was '" + location + "'");
058        }
059        
060        String pluginName = m.group(1);
061        String optional = m.group(2);
062        String path = m.group(3);
063        
064        String resourceURI = PluginsManager.getInstance().getResourceURI(pluginName);
065        
066        if (resourceURI == null)
067        {
068            File pluginLocation = PluginsManager.getInstance().getPluginLocation(pluginName);
069            if (pluginLocation == null)
070            {
071                if (optional == null)
072                {
073                    String errorMessage = "The plugin '" + pluginName + "' does not exist.";
074                    getLogger().warn(errorMessage);
075                    
076                    throw new SourceNotFoundException(errorMessage);
077                }
078                else
079                {
080                    String fallback = _getOptionalSourceFallbackExtensionPoint().fallback(location);
081                    if (fallback == null)
082                    {
083                        String errorMessage = "While resolving the url '" + location + "', the plugin '" + pluginName + "' does not exist and no fallback is matching it.";
084                        getLogger().warn(errorMessage);
085                        throw new SourceNotFoundException(errorMessage);
086                    }
087                    
088                    try
089                    {
090                        Source source = _resolver.resolveURI(fallback);
091                        if (!source.exists())
092                        {
093                            String errorMessage = "While resolving the url '" + location + "', the plugin '" + pluginName + "' does not exist and the fallback '" + fallback + "' does not exist.";
094                            getLogger().warn(errorMessage);
095                            throw new SourceNotFoundException(errorMessage);
096                        }
097                        return source;
098                    }
099                    catch (SourceNotFoundException e)
100                    {
101                        throw new SourceNotFoundException("While resolving the url '" + location + "', the plugin '" + pluginName + "' does not exist and the fallback '" + fallback + "' does not exist.", e);
102                    }
103                }
104            }
105             
106            return new FileSource("file", new File(pluginLocation, path));
107        }
108        else
109        {
110            return _resolver.resolveURI(resourceURI + '/' + path);
111        }
112    }
113    
114    public void release(Source source)
115    {
116        // empty method
117    }
118
119    private synchronized OptionalSourceFallbackExtensionPoint _getOptionalSourceFallbackExtensionPoint()
120    {
121        if (_optionalSourceFallbackExtensionPoint == null)
122        {
123            try
124            {
125                _optionalSourceFallbackExtensionPoint = (OptionalSourceFallbackExtensionPoint) _manager.lookup(OptionalSourceFallbackExtensionPoint.ROLE);
126            }
127            catch (ServiceException e)
128            {
129                throw new RuntimeException("Unable to get the OptionalSourceFallbacksExtensionPoint extension point.", e);
130            }
131        }
132        return _optionalSourceFallbackExtensionPoint;
133    }
134    
135    public void service(ServiceManager manager) throws ServiceException
136    {
137        _manager = manager;
138        _resolver = (SourceResolver) manager.lookup(SourceResolver.ROLE);
139    }
140}