001    /**
002     * Copyright (c) 2000-2012 Liferay, Inc. All rights reserved.
003     *
004     * This library is free software; you can redistribute it and/or modify it under
005     * the terms of the GNU Lesser General Public License as published by the Free
006     * Software Foundation; either version 2.1 of the License, or (at your option)
007     * any later version.
008     *
009     * This library is distributed in the hope that it will be useful, but WITHOUT
010     * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
011     * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
012     * details.
013     */
014    
015    package com.liferay.portal.servlet.filters.etag;
016    
017    import com.liferay.portal.kernel.servlet.ByteBufferServletResponse;
018    import com.liferay.portal.kernel.servlet.ServletResponseUtil;
019    import com.liferay.portal.kernel.util.ParamUtil;
020    import com.liferay.portal.servlet.filters.BasePortalFilter;
021    
022    import javax.servlet.FilterChain;
023    import javax.servlet.http.HttpServletRequest;
024    import javax.servlet.http.HttpServletResponse;
025    
026    /**
027     * @author Eduardo Lundgren
028     * @author Brian Wing Shun Chan
029     * @author Raymond Augé
030     * @author Shuyang Zhou
031     */
032    public class ETagFilter extends BasePortalFilter {
033    
034            @Override
035            public boolean isFilterEnabled(
036                    HttpServletRequest request, HttpServletResponse response) {
037    
038                    if (ParamUtil.getBoolean(request, _ETAG, true)) {
039                            return true;
040                    }
041                    else {
042                            return false;
043                    }
044            }
045    
046            @Override
047            protected void processFilter(
048                            HttpServletRequest request, HttpServletResponse response,
049                            FilterChain filterChain)
050                    throws Exception {
051    
052                    ByteBufferServletResponse byteBufferResponse =
053                            new ByteBufferServletResponse(response);
054    
055                    processFilter(
056                            ETagFilter.class, request, byteBufferResponse, filterChain);
057    
058                    if (!ETagUtil.processETag(request, response, byteBufferResponse)) {
059                            ServletResponseUtil.write(
060                                    response, byteBufferResponse.getByteBuffer());
061                    }
062            }
063    
064            private static final String _ETAG = "etag";
065    
066    }