    001// Copyright 2009, 2010, 2012 The Apache Software Foundation
    002//
    003// Licensed under the Apache License, Version 2.0 (the "License");
    004// you may not use this file except in compliance with the License.
    005// You may obtain a copy of the License at
    006//
    007// http://www.apache.org/licenses/LICENSE-2.0
    008//
    009// Unless required by applicable law or agreed to in writing, software
    010// distributed under the License is distributed on an "AS IS" BASIS,
    011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012// See the License for the specific language governing permissions and
    013// limitations under the License.
    014
    015package org.apache.tapestry5.http.internal.gzip;
    016
    017import java.io.IOException;
    018
    019import javax.servlet.ServletOutputStream;
    020import javax.servlet.http.HttpServletRequest;
    021import javax.servlet.http.HttpServletResponse;
    022import javax.servlet.http.HttpServletResponseWrapper;
    023
    024import org.apache.tapestry5.http.TapestryHttpConstants;
    025import org.apache.tapestry5.http.services.CompressionAnalyzer;
    026
    027public class GZIPEnabledResponse extends HttpServletResponseWrapper
    028{
    029    private final int cutover;
    030
    031    private final HttpServletRequest request;
    032
    033    private final HttpServletResponse response;
    034
    035    private final CompressionAnalyzer analyzer;
    036
    037    private boolean contentLengthSet = false;
    038
    039    public GZIPEnabledResponse(HttpServletResponse response, HttpServletRequest request, int cutover,
    040                               CompressionAnalyzer analyzer)
    041    {
    042        super(response);
    043
    044        this.request = request;
    045        this.response = response;
    046        this.cutover = cutover;
    047        this.analyzer = analyzer;
    048    }
    049
    050    public void setContentLength(int len)
    051    {
    052        super.setContentLength(len);
    053
    054        contentLengthSet = true;
    055    }
    056
    057    @Override
    058    public ServletOutputStream getOutputStream() throws IOException
    059    {
    060        if (contentLengthSet || isCompressionDisabled())
    061            return super.getOutputStream();
    062
    063        String contentType = getContentType();
    064
    065        return new BufferedGZipOutputStream(contentType, response, cutover, analyzer);
    066    }
    067
    068    private boolean isCompressionDisabled()
    069    {
    070        return request.getAttribute(TapestryHttpConstants.SUPPRESS_COMPRESSION) != null;
    071    }
    072}