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}