001    // Copyright 2010 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.tapestry5.internal.services.assets;
016    
017    import java.io.IOException;
018    
019    import org.apache.tapestry5.internal.services.AssetResourceLocator;
020    import org.apache.tapestry5.internal.services.ResourceStreamer;
021    import org.apache.tapestry5.ioc.Resource;
022    import org.apache.tapestry5.services.ClasspathAssetAliasManager;
023    import org.apache.tapestry5.services.Request;
024    import org.apache.tapestry5.services.Response;
025    import org.apache.tapestry5.services.assets.AssetRequestHandler;
026    
027    /**
028     * A handler for asset requests for classpath assets (within a specific folder).
029     * Each mapping of the {@link ClasspathAssetAliasManager} gets one of these.
030     * 
031     * @since 5.2.0
032     */
033    public class ClasspathAssetRequestHandler implements AssetRequestHandler
034    {
035        private final ResourceStreamer streamer;
036    
037        private final AssetResourceLocator assetResourceLocator;
038    
039        private final String baseFolder;
040    
041        public ClasspathAssetRequestHandler(ResourceStreamer streamer, AssetResourceLocator assetResourceLocator,
042                String baseFolder)
043        {
044            this.streamer = streamer;
045            this.assetResourceLocator = assetResourceLocator;
046            this.baseFolder = baseFolder;
047        }
048    
049        public boolean handleAssetRequest(Request request, Response response, String extraPath) throws IOException
050        {
051            String assetPath = baseFolder + "/" + extraPath;
052    
053            Resource resource = assetResourceLocator.findClasspathResourceForPath(assetPath);
054    
055            if (resource == null)
056                return false;
057    
058            streamer.streamResource(resource);
059    
060            return true;
061        }
062    }