/*
 * 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.impl;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;

/**
 * 当开始写http content的时候，通知其它request context提交其headers。在此之后将不能修改headers。
 *
 * @author Michael Zhou
 */
class CommittingAwareResponse extends HttpServletResponseWrapper {
    private final HeaderCommitter     committer;
    private       ServletOutputStream stream;
    private       PrintWriter         writer;

    public CommittingAwareResponse(HttpServletResponse response, HeaderCommitter committer) {
        super(response);
        this.committer = committer;
    }

    @Override
    public ServletOutputStream getOutputStream() throws IOException {
        if (stream == null) {
            stream = new CommittingAwareServletOutputStream(committer, super.getOutputStream());
        }

        return stream;
    }

    @Override
    public PrintWriter getWriter() throws IOException {
        if (writer == null) {
            writer = new CommittingAwarePrintWriter(committer, super.getWriter());
        }

        return writer;
    }

    @Override
    public String toString() {
        return getResponse().toString();
    }
}