001/*
002 * Copyright 2002-2017 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.http.server;
018
019import java.io.IOException;
020import java.util.concurrent.atomic.AtomicBoolean;
021import javax.servlet.AsyncContext;
022import javax.servlet.AsyncEvent;
023import javax.servlet.AsyncListener;
024import javax.servlet.http.HttpServletRequest;
025import javax.servlet.http.HttpServletResponse;
026
027import org.springframework.util.Assert;
028
029/**
030 * A {@link ServerHttpAsyncRequestControl} to use on Servlet containers (Servlet 3.0+).
031 *
032 * @author Rossen Stoyanchev
033 * @since 4.0
034 */
035public class ServletServerHttpAsyncRequestControl implements ServerHttpAsyncRequestControl, AsyncListener {
036
037        private static final long NO_TIMEOUT_VALUE = Long.MIN_VALUE;
038
039
040        private final ServletServerHttpRequest request;
041
042        private final ServletServerHttpResponse response;
043
044        private AsyncContext asyncContext;
045
046        private AtomicBoolean asyncCompleted = new AtomicBoolean(false);
047
048
049        /**
050         * Constructor accepting a request and response pair that are expected to be of type
051         * {@link ServletServerHttpRequest} and {@link ServletServerHttpResponse}
052         * respectively.
053         */
054        public ServletServerHttpAsyncRequestControl(ServletServerHttpRequest request, ServletServerHttpResponse response) {
055                Assert.notNull(request, "request is required");
056                Assert.notNull(response, "response is required");
057
058                Assert.isTrue(request.getServletRequest().isAsyncSupported(),
059                                "Async support must be enabled on a servlet and for all filters involved " +
060                                "in async request processing. This is done in Java code using the Servlet API " +
061                                "or by adding \"<async-supported>true</async-supported>\" to servlet and " +
062                                "filter declarations in web.xml. Also you must use a Servlet 3.0+ container");
063
064                this.request = request;
065                this.response = response;
066        }
067
068
069        @Override
070        public boolean isStarted() {
071                return (this.asyncContext != null && this.request.getServletRequest().isAsyncStarted());
072        }
073
074        @Override
075        public boolean isCompleted() {
076                return this.asyncCompleted.get();
077        }
078
079        @Override
080        public void start() {
081                start(NO_TIMEOUT_VALUE);
082        }
083
084        @Override
085        public void start(long timeout) {
086                Assert.state(!isCompleted(), "Async processing has already completed");
087                if (isStarted()) {
088                        return;
089                }
090
091                HttpServletRequest servletRequest = this.request.getServletRequest();
092                HttpServletResponse servletResponse = this.response.getServletResponse();
093
094                this.asyncContext = servletRequest.startAsync(servletRequest, servletResponse);
095                this.asyncContext.addListener(this);
096
097                if (timeout != NO_TIMEOUT_VALUE) {
098                        this.asyncContext.setTimeout(timeout);
099                }
100        }
101
102        @Override
103        public void complete() {
104                if (isStarted() && !isCompleted()) {
105                        this.asyncContext.complete();
106                }
107        }
108
109
110        // ---------------------------------------------------------------------
111        // Implementation of AsyncListener methods
112        // ---------------------------------------------------------------------
113
114        @Override
115        public void onComplete(AsyncEvent event) throws IOException {
116                this.asyncContext = null;
117                this.asyncCompleted.set(true);
118        }
119
120        @Override
121        public void onStartAsync(AsyncEvent event) throws IOException {
122        }
123
124        @Override
125        public void onError(AsyncEvent event) throws IOException {
126        }
127
128        @Override
129        public void onTimeout(AsyncEvent event) throws IOException {
130        }
131
132}