001    // Copyright 2005 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    
015    package org.apache.tapestry.services.impl;
016    
017    import java.io.IOException;
018    
019    import org.apache.hivemind.ErrorLog;
020    import org.apache.hivemind.HiveMind;
021    import org.apache.tapestry.services.ResetEventHub;
022    import org.apache.tapestry.services.WebRequestServicer;
023    import org.apache.tapestry.services.WebRequestServicerFilter;
024    import org.apache.tapestry.web.WebRequest;
025    import org.apache.tapestry.web.WebResponse;
026    
027    /**
028     * Filter whose job is to invoke
029     * {@link org.apache.tapestry.services.ResetEventHub#fireResetEvent()}after the request has
030     * been processed. This filter is only contributed into the
031     * tapestry.request.WebRequestServicerPipeline configuration if the
032     * org.apache.tapestry.disable-caching system property is true.
033     * 
034     * @author Howard M. Lewis Ship
035     * @since 4.0
036     */
037    public class DisableCachingFilter implements WebRequestServicerFilter
038    {
039        private ErrorLog _errorLog;
040    
041        private ResetEventHub _resetEventHub;
042    
043        public void service(WebRequest request, WebResponse response, WebRequestServicer servicer)
044                throws IOException
045        {
046            try
047            {
048                servicer.service(request, response);
049            }
050            finally
051            {
052                fireResetEvent();
053            }
054    
055        }
056    
057        private void fireResetEvent()
058        {
059            try
060            {
061                _resetEventHub.fireResetEvent();
062            }
063            catch (Exception ex)
064            {
065                _errorLog.error(ImplMessages.errorResetting(ex), HiveMind.getLocation(ex), ex);
066            }
067        }
068    
069        public void setResetEventHub(ResetEventHub resetEventCoordinator)
070        {
071            _resetEventHub = resetEventCoordinator;
072        }
073    
074        public void setErrorLog(ErrorLog errorLog)
075        {
076            _errorLog = errorLog;
077        }
078    }