org.springframework.web.servlet.mvc.LastModified Maven / Gradle / Ivy
/*
* Copyright 2002-2006 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
*
* http://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.mvc;
import javax.servlet.http.HttpServletRequest;
/**
* Supports last-modified HTTP requests to facilitate content caching.
* Same contract as for the Servlet API's getLastModified method.
*
* Delegated to by a HandlerAdapter's getLastModified implementation.
* By default, any Controller or HttpRequestHandler within Spring's default framework
* can implement this interface to enable last-modified checking.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @see javax.servlet.http.HttpServlet#getLastModified
* @see Controller
* @see SimpleControllerHandlerAdapter
* @see org.springframework.web.HttpRequestHandler
* @see HttpRequestHandlerAdapter
*/
public interface LastModified {
/**
* Same contract as for HttpServlet's getLastModified method.
* Invoked before request processing.
*
The return value will be sent to the HTTP client as Last-Modified header,
* and compared with If-Modified-Since headers that the client sends back.
* The content will only get regenerated if there has been a modification.
* @param request current HTTP request
* @return the time the underlying resource was last modified, or -1
* meaning that the content must always be regenerated
* @see org.springframework.web.servlet.HandlerAdapter#getLastModified
* @see javax.servlet.http.HttpServlet#getLastModified
*/
long getLastModified(HttpServletRequest request);
}