https://github.com/spring-projects/spring-framework: Spring Web MVC (Spring IO)
  • Juergen Hoeller 
/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.servlet.resource;

import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.springframework.core.io.Resource;
import org.springframework.lang.Nullable;


A contract for invoking a chain of ResourceResolvers where each resolver is given a reference to the chain allowing it to delegate when necessary. 
Author:Jeremy Grelle, Rossen Stoyanchev, Sam Brannen
Since:4.1
/**
 * A contract for invoking a chain of {@link ResourceResolver ResourceResolvers} where each resolver
 * is given a reference to the chain allowing it to delegate when necessary.
 *
 * @author Jeremy Grelle
 * @author Rossen Stoyanchev
 * @author Sam Brannen
 * @since 4.1
 */
public interface ResourceResolverChain {

	
Resolve the supplied request and request path to a Resource that exists under one of the given resource locations. 
Params:
  • request – the current request
  • requestPath – the portion of the request path to use
  • locations – the locations to search in when looking up resources
Returns:the resolved resource, or null if unresolved
/**
	 * Resolve the supplied request and request path to a {@link Resource} that
	 * exists under one of the given resource locations.
	 * @param request the current request
	 * @param requestPath the portion of the request path to use
	 * @param locations the locations to search in when looking up resources
	 * @return the resolved resource, or {@code null} if unresolved
	 */
	@Nullable
	Resource resolveResource(
			@Nullable HttpServletRequest request, String requestPath, List<? extends Resource> locations);

	
Resolve the externally facing public URL path for clients to use
to access the resource that is located at the given internal
resource path.

This is useful when rendering URL links to clients.

Params:
  • resourcePath – the internal resource path
  • locations – the locations to search in when looking up resources
Returns:the resolved public URL path, or null if unresolved
/**
	 * Resolve the externally facing <em>public</em> URL path for clients to use
	 * to access the resource that is located at the given <em>internal</em>
	 * resource path.
	 * <p>This is useful when rendering URL links to clients.
	 * @param resourcePath the internal resource path
	 * @param locations the locations to search in when looking up resources
	 * @return the resolved public URL path, or {@code null} if unresolved
	 */
	@Nullable
	String resolveUrlPath(String resourcePath, List<? extends Resource> locations);

}