org.springframework.web.servlet.AsyncHandlerInterceptor Maven / Gradle / Ivy
/*
* Copyright 2002-2012 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;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.method.HandlerMethod;
/**
* Extends {@code HandlerInterceptor} with a callback method invoked during
* asynchronous request handling.
*
* When a handler starts asynchronous request handling, the DispatcherServlet
* exits without invoking {@code postHandle} and {@code afterCompletion}, as it
* normally does, since the results of request handling (e.g. ModelAndView)
* will. be produced concurrently in another thread. In such scenarios,
* {@link #afterConcurrentHandlingStarted(HttpServletRequest, HttpServletResponse, Object)}
* is invoked instead allowing implementations to perform tasks such as cleaning
* up thread bound attributes.
*
*
When asynchronous handling completes, the request is dispatched to the
* container for further processing. At this stage the DispatcherServlet invokes
* {@code preHandle}, {@code postHandle} and {@code afterCompletion} as usual.
*
* @author Rossen Stoyanchev
* @since 3.2
*
* @see org.springframework.web.context.request.async.WebAsyncManager
* @see org.springframework.web.context.request.async.CallableProcessingInterceptor
* @see org.springframework.web.context.request.async.DeferredResultProcessingInterceptor
*/
public interface AsyncHandlerInterceptor extends HandlerInterceptor {
/**
* Called instead of {@code postHandle} and {@code afterCompletion}, when
* the a handler is being executed concurrently. Implementations may use the
* provided request and response but should avoid modifying them in ways
* that would conflict with the concurrent execution of the handler. A
* typical use of this method would be to clean thread local variables.
*
* @param request the current request
* @param response the current response
* @param handler handler (or {@link HandlerMethod}) that started async
* execution, for type and/or instance examination
* @throws Exception in case of errors
*/
void afterConcurrentHandlingStarted(
HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception;
}