/*

  * Copyright 2006-2008 The Kuali Foundation

  * 

  * Licensed under the Educational Community License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  * 

  * http://www.opensource.org/licenses/ecl2.php

  * 

  * 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 org.kuali.rice.kns.web.filter;

 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 org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 /**

  * This class can be used to increase the response buffer size so that if there is a late exception, Tomcat's ErrorReportValve can

  * display it on the page and return an error status in the HTTP reponse header. This filter must be configured early in the chain

  * in web.xml, before another filter writes anything to the response.

  * 

  * There's no configuration option for this already?

  * 

  * 

  */

 public class SetResponseBufferSizeFilter implements Filter {

     private Log log;

     private int bufferSize;

     /**

      * Initializes this Filter with the required parameter, bufferSize.

      * 

      * @throws ServletException if the bufferSize parameter is missing or does not contain an integer.

      * @see Filter#init

      */

     public void init(FilterConfig filterConfig) throws ServletException {

         log = LogFactory.getLog(SetResponseBufferSizeFilter.class);

         String bufferSizeParam = filterConfig.getInitParameter("bufferSize");

         if (log.isDebugEnabled()) {

             log.debug("bufferSizeParam=" + bufferSizeParam);

         }

         if (bufferSizeParam == null) {

             throw new ServletException("bufferSize parameter is required");

         }

         try {

             bufferSize = Integer.parseInt(bufferSizeParam);

         }

         catch (NumberFormatException e) {

             throw new ServletException("bufferSize parameter is not an integer", e);

         }

         log.info("Filter initialized. Response buffer size is " + bufferSize);

     }

     /**

      * Sets the bufferSize of the response.

      * 

      * @see Filter#doFilter

      */

     public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

         if (log.isDebugEnabled()) {

             log.debug("setting response buffer size to " + bufferSize);

         }

         servletResponse.setBufferSize(bufferSize);

         filterChain.doFilter(servletRequest, servletResponse);

     }

     /**

      * Does nothing.

      * 

      * @see Filter#destroy

      */

     public void destroy() {

         // nothing to destroy

     }

 }