    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.internal.gzip;
    016
    017import org.apache.tapestry5.internal.InternalConstants;
    018import org.apache.tapestry5.services.assets.CompressionAnalyzer;
    019
    020import javax.servlet.ServletOutputStream;
    021import javax.servlet.http.HttpServletRequest;
    022import javax.servlet.http.HttpServletResponse;
    023import javax.servlet.http.HttpServletResponseWrapper;
    024import java.io.IOException;
    025
    026public class GZIPEnabledResponse extends HttpServletResponseWrapper
    027{
    028    private final int cutover;
    029
    030    private final HttpServletRequest request;
    031
    032    private final HttpServletResponse response;
    033
    034    private final CompressionAnalyzer analyzer;
    035
    036    private boolean contentLengthSet = false;
    037
    038    public GZIPEnabledResponse(HttpServletResponse response, HttpServletRequest request, int cutover,
    039                               CompressionAnalyzer analyzer)
    040    {
    041        super(response);
    042
    043        this.request = request;
    044        this.response = response;
    045        this.cutover = cutover;
    046        this.analyzer = analyzer;
    047    }
    048
    049    public void setContentLength(int len)
    050    {
    051        super.setContentLength(len);
    052
    053        contentLengthSet = true;
    054    }
    055
    056    @Override
    057    public ServletOutputStream getOutputStream() throws IOException
    058    {
    059        if (contentLengthSet || isCompressionDisabled())
    060            return super.getOutputStream();
    061
    062        String contentType = getContentType();
    063
    064        return new BufferedGZipOutputStream(contentType, response, cutover, analyzer);
    065    }
    066
    067    private boolean isCompressionDisabled()
    068    {
    069        return request.getAttribute(InternalConstants.SUPPRESS_COMPRESSION) != null;
    070    }
    071}