001/*
002 * Copyright 2002-2018 the original author or authors.
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 *      https://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 */
016
017package org.springframework.web.servlet.resource;
018
019import java.io.IOException;
020
021import javax.servlet.http.HttpServletRequest;
022
023import org.springframework.core.io.Resource;
024
025/**
026 * A contract for invoking a chain of {@link ResourceTransformer ResourceTransformers} where each resolver
027 * is given a reference to the chain allowing it to delegate when necessary.
028 *
029 * @author Rossen Stoyanchev
030 * @since 4.1
031 */
032public interface ResourceTransformerChain {
033
034        /**
035         * Return the {@code ResourceResolverChain} that was used to resolve the
036         * {@code Resource} being transformed. This may be needed for resolving
037         * related resources, e.g. links to other resources.
038         */
039        ResourceResolverChain getResolverChain();
040
041        /**
042         * Transform the given resource.
043         * @param request the current request
044         * @param resource the candidate resource to transform
045         * @return the transformed or the same resource, never {@code null}
046         * @throws IOException if transformation fails
047         */
048        Resource transform(HttpServletRequest request, Resource resource) throws IOException;
049
050}