001    /**
002     * Copyright (c) 2000-2011 Liferay, Inc. All rights reserved.
003     *
004     * The contents of this file are subject to the terms of the Liferay Enterprise
005     * Subscription License ("License"). You may not use this file except in
006     * compliance with the License. You can obtain a copy of the License by
007     * contacting Liferay, Inc. See the License for the specific language governing
008     * permissions and limitations under the License, including but not limited to
009     * distribution rights of the Software.
010     *
011     *
012     *
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    }