/*
* Copyright (c) 2002-2012 Alibaba Group Holding Limited.
* All rights reserved.
*
* 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 com.alibaba.citrus.service.requestcontext.lazycommit.impl;
import java.io.IOException;
import javax.servlet.http.HttpServletResponse;
import com.alibaba.citrus.service.requestcontext.RequestContext;
import com.alibaba.citrus.service.requestcontext.lazycommit.LazyCommitFailedException;
import com.alibaba.citrus.service.requestcontext.lazycommit.LazyCommitRequestContext;
import com.alibaba.citrus.service.requestcontext.support.AbstractRequestContextWrapper;
import com.alibaba.citrus.service.requestcontext.support.AbstractResponseWrapper;
import com.alibaba.citrus.util.StringUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* 延迟提交response的实现。
*
* @author Michael Zhou
*/
public class LazyCommitRequestContextImpl extends AbstractRequestContextWrapper implements LazyCommitRequestContext {
private final static Logger log = LoggerFactory.getLogger(LazyCommitRequestContext.class);
private SendError sendError;
private String sendRedirect;
private boolean setLocation;
private boolean bufferFlushed;
private int status;
/**
* 包装一个<code>RequestContext</code>对象。
*
* @param wrappedContext 被包装的<code>RequestContext</code>
*/
public LazyCommitRequestContextImpl(RequestContext wrappedContext) {
super(wrappedContext);
setResponse(new ResponseWrapper(wrappedContext.getResponse()));
}
/**
* 判断当前请求是否已出错。
*
* @return 如果出错，则返回<code>true</code>
*/
public boolean isError() {
return sendError != null;
}
/**
* 如果<code>sendError()</code>方法曾被调用，则该方法返回一个error状态值。
*
* @return error状态值，若系统正常，则返回<code>0</code>
*/
public int getErrorStatus() {
if (sendError != null) {
return sendError.status;
}
return 0;
}
/**
* 如果<code>sendError()</code>方法曾被调用，则该方法返回一个error信息。
*
* @return error信息，若系统正常，则返回<code>null</code>
*/
public String getErrorMessage() {
if (sendError != null) {
return sendError.message;
}
return null;
}
/**
* 判断当前请求是否已被重定向。
*
* @return 如果重定向，则返回<code>true</code>
*/
public boolean isRedirected() {
return setLocation || !StringUtil.isEmpty(sendRedirect);
}
/**
* 取得重定向的URI。
*
* @return 重定向的URI，如果没有重定向，则返回<code>null</code>
*/
public String getRedirectLocation() {
return sendRedirect;
}
/**
* 取得最近设置的HTTP status。
*
* @return HTTP status值
*/
public int getStatus() {
return status;
}
@Override
public void commitHeaders() throws LazyCommitFailedException {
try {
((ResponseWrapper) getResponse()).commitHeaders();
} catch (IOException e) {
throw new LazyCommitFailedException(e);
}
}
/**
* 结束一个请求。
*
* @throws LazyCommitFailedException 如果失败
*/
@Override
public void commit() throws LazyCommitFailedException {
try {
((ResponseWrapper) getResponse()).commit();
} catch (IOException e) {
throw new LazyCommitFailedException(e);
}
}
/** 包装response。 */
private class ResponseWrapper extends AbstractResponseWrapper {
private boolean headersCommitted;
public ResponseWrapper(HttpServletResponse response) {
super(LazyCommitRequestContextImpl.this, response);
}
@Override
public void sendError(int status) throws IOException {
sendError(status, null);
}
@Override
public void sendError(int status, String message) throws IOException {
if (sendError == null && sendRedirect == null) {
sendError = new SendError(status, message);
if (headersCommitted) {
super.sendError(status, message);
}
}
}
/**
* 设置重定向URI。
*
* @param location 重定向的URI
* @throws IOException 输入输出失败
* @throws IllegalStateException 如果response已经committed
*/
@Override
public void sendRedirect(String location) throws IOException {
if (sendError == null && sendRedirect == null) {
sendRedirect = location;
if (headersCommitted) {
super.sendRedirect(location);
}
}
}
@Override
public void setHeader(String key, String value) {
if ("location".equalsIgnoreCase(key)) {
setLocation = true;
}
super.setHeader(key, value);
}
@Override
public void flushBuffer() throws IOException {
bufferFlushed = true;
if (headersCommitted) {
super.flushBuffer();
}
}
/**
* 设置HTTP status。
*
* @param sc HTTP status值
*/
@Override
public void setStatus(int sc) {
status = sc;
if (headersCommitted) {
super.setStatus(sc);
}
}
@Override
public void reset() {
super.reset();
sendError = null;
sendRedirect = null;
setLocation = false;
bufferFlushed = false;
status = 0;
}
private void commitHeaders() throws IOException {
headersCommitted = true;
if (status > 0) {
log.debug("Set HTTP status to " + status);
super.setStatus(status);
}
if (sendError != null) {
if (sendError.message == null) {
log.debug("Set error page: " + sendError.status);
super.sendError(sendError.status);
} else {
log.debug("Set error page: " + sendError.status + " " + sendError.message);
super.sendError(sendError.status, sendError.message);
}
} else if (sendRedirect != null) {
log.debug("Set redirect location to " + sendRedirect);
// 将location用输出编码转换一下，这样可以确保包含非US_ASCII字符的URL正确输出
String charset = getCharacterEncoding();
if (charset != null) {
sendRedirect = new String(sendRedirect.getBytes(charset), "8859_1");
}
super.sendRedirect(sendRedirect);
}
}
private void commit() throws IOException {
if (bufferFlushed) {
super.flushBuffer();
}
}
}
/** 保存sendError的信息。 */
private class SendError {
public final int status;
public final String message;
public SendError(int status, String message) {
this.status = status;
this.message = message;
}
}
}