/*

  * This software is licensed under the Apache License, Version 2.0

  * (the "License") agreement; you may not use this file except in compliance with

  * the License.  You may obtain a copy of the License at

  * 

  *      http://www.apache.org/licenses/LICENSE-2.0

  * 

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package net.admin4j.ui.filters;

 import java.io.IOException;

 import javax.servlet.Filter;

 import javax.servlet.FilterChain;

 import javax.servlet.FilterConfig;

 import javax.servlet.ServletException;

 import javax.servlet.ServletRequest;

 import javax.servlet.ServletResponse;

 import javax.servlet.http.HttpServletRequest;

 import net.admin4j.config.Admin4JConfiguration;

 import net.admin4j.deps.commons.lang3.StringUtils;

 import net.admin4j.util.Admin4jRuntimeException;

 import net.admin4j.util.FixedSizeRollingList;

 import net.admin4j.util.ServletUtils;

 import net.admin4j.vo.HttpRequestVO;

 /**

  * Filter that will track requests in a session for possible error reporting. 

  * @author D. Ashmore

  * @since 1.0.2

  */

 public class RequestTrackingFilter implements Filter {

     public static final int DEFAULT_NBR_REQUESTS_TRACKED = 5;

     public static final String REQUEST_TRACKING_SESSION_ATTRIBUTE_NAME = "admin4j.previous.requests";

     private int nbrRequestsTracked;

     public void destroy() {

         // NoOp

     }

     @SuppressWarnings("unchecked")

     public void doFilter(ServletRequest request, ServletResponse response,

             FilterChain chain) throws IOException, ServletException {

         HttpServletRequest httpRequest = (HttpServletRequest)request;

         FixedSizeRollingList<HttpRequestVO> list = (FixedSizeRollingList<HttpRequestVO>)

                 httpRequest.getSession().getAttribute(REQUEST_TRACKING_SESSION_ATTRIBUTE_NAME);

         if (list == null) {

             list = new FixedSizeRollingList<HttpRequestVO>(nbrRequestsTracked);

             httpRequest.getSession().setAttribute(REQUEST_TRACKING_SESSION_ATTRIBUTE_NAME, list);

         }

         list.add(new HttpRequestVO(httpRequest.getRequestURI(), 

                 ServletUtils.listRequestAttributes(httpRequest)));

         chain.doFilter(request, response);

     }

     public void init(FilterConfig config) throws ServletException {

         String nbrRequestsStr = config.getInitParameter("nbr.requests.tracked");

         if (Admin4JConfiguration.getRequestHistoryNbrRetained() != null) {

             if (Admin4JConfiguration.getRequestHistoryNbrRetained() > 0) {

                 nbrRequestsTracked = Admin4JConfiguration.getRequestHistoryNbrRetained();

             }

             else {

                 throw new Admin4jRuntimeException("request.history.nbr.retained must be greater than zero")

                 .addContextValue("request.history.nbr.retained", Admin4JConfiguration.getRequestHistoryNbrRetained());

             }

         }

         else if (StringUtils.isEmpty(nbrRequestsStr)) {

             nbrRequestsTracked = DEFAULT_NBR_REQUESTS_TRACKED;

         }

         else {

             try {

                 nbrRequestsTracked = Integer.valueOf(nbrRequestsStr);

             } catch (NumberFormatException e) {

                 throw new Admin4jRuntimeException("request.history.nbr.retained must be numeric")

                 .addContextValue("request.history.nbr.retained", nbrRequestsStr);

             }

         }

         Admin4JStandardFilterChain.registerFilter(this);

     }

 }