001// Copyright 2011, 2012 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.services.assets; 016 017import org.apache.tapestry5.ioc.Resource; 018import org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration; 019 020import java.io.IOException; 021import java.util.Set; 022 023/** 024 * Converts {@link Resource}s into {@link StreamableResource}s, and may be responsible for 025 * {@linkplain ResourceTransformer transforming} resources based on file extension. Contributions map a file extension 026 * (such as "coffee") to a transformer for that file extension. 027 * Service decorators added to this service may provide additional processing (compression, minimization, and caching). 028 * 029 * @since 5.3 030 */ 031@UsesMappedConfiguration(ResourceTransformer.class) 032public interface StreamableResourceSource 033{ 034 /** 035 * Given a desired content type, identify which file extensions can be mapped to that extension based on 036 * contributed {@link ResourceTransformer}s that can 037 * {@linkplain org.apache.tapestry5.services.assets.ResourceTransformer#getTransformedContentType() produce the content type} 038 * based for a file with that extension. 039 * 040 * @param contentType 041 * to search for 042 * @return set of file extension, possibly empty, in no particular order. These are the bare extensions, i.e. 043 * "js", "coffee". 044 * @since 5.4 045 */ 046 Set<String> fileExtensionsForContentType(String contentType); 047 048 /** 049 * Converts a Resource (which must be non-null and exist) into a streamable resource, along with 050 * some additional optional behaviors. 051 * 052 * @param baseResource 053 * the resource to convert 054 * @param processing 055 * defines additional processing after the resource has been read and possibly transformed 056 * @param dependencies 057 * Passed to any {@link ResourceTransformer} to track additional dependencies of the base resource 058 * @return the contents of the Resource, possibly transformed, in a streamable format. 059 * @throws IOException 060 * if the resource does not exist or a URL for the content is not available 061 */ 062 StreamableResource getStreamableResource(Resource baseResource, StreamableResourceProcessing processing, ResourceDependencies dependencies) 063 throws IOException; 064}