/*
    * $Id: TilesFilter.java 531864 2007-04-24 10:24:30Z apetrelli $
    *
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache 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.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 org.apache.tiles.web.startup;
  
  import java.io.IOException;
  import java.util.Enumeration;
  
  import javax.servlet.Filter;
  import javax.servlet.FilterChain;
  import javax.servlet.FilterConfig;
  import javax.servlet.ServletConfig;
  import javax.servlet.ServletContext;
  import javax.servlet.ServletException;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.tiles.definition.util.DefinitionsFactoryUtil;
  
  /***
   * Processes Reloadable Tiles Definitions.
   *
   * @version $Rev: 531864 $ $Date: 2007-04-24 12:24:30 +0200 (Tue, 24 Apr 2007) $
   */
  
  public class TilesFilter extends TilesServlet implements Filter {
  
      /***
       * The logging object.
       */
      @SuppressWarnings("unused")
      private static final Log LOG = LogFactory.getLog(TilesFilter.class);
  
      /***
       * The filter configuration object we are associated with.  If
       * this value is null, this filter instance is not currently
       * configured.
       */
      private FilterConfig filterConfig = null;
  
  
      /***
       * Checks whether Tiles Definitions need to be reloaded.
       *
       * @param request  The servlet request we are processing
       * @param response The servlet response we are creating
       * @param chain    The filter chain we are processing
       * @throws IOException      if an input/output error occurs
       * @throws ServletException if a servlet error occurs
       */
      public void doFilter(ServletRequest request, ServletResponse response,
                           FilterChain chain)
          throws IOException, ServletException {
  
          try {
              DefinitionsFactoryUtil.reloadDefinitionsFactory(
                      getServletContext());
              chain.doFilter(request, response);
          } catch (Exception e) {
              throw new ServletException("Error processing request.", e);
          }
      }
  
      /***
       * Returns the filter configuration object for this filter.
       *
       * @return The filter configuration.
       */
      public FilterConfig getFilterConfig() {
          return (this.filterConfig);
      }
  
      /***
       * Set the filter configuration object for this filter.
       *
       * @param filterConfig The filter configuration object
       */
      public void setFilterConfig
          (FilterConfig
             filterConfig) {
 
         this.filterConfig = filterConfig;
     }
 
     /***
      * Destroy method for this filter.
      */
     public void destroy
         () {
         super.destroy();
     }
 
     /*** {@inheritDoc} */
     public void init(FilterConfig filterConfig) throws ServletException {
         this.filterConfig = filterConfig;
         super.init(createServletConfig());
 
         if (DEBUG) {
             log("TilesDecorationFilter:Initializing filter");
         }
     }
 
     /*** {@inheritDoc} */
     public void log(String msg) {
         filterConfig.getServletContext().log(msg);
     }
 
     /***
      * A DEBUG flag.
      */
     // FIXME Is it really used?
     private static final boolean DEBUG = true;
 
     /***
      * Creates a servlet configuration object from the filter configuration
      * object.
      *
      * @return The servlet configuration object.
      */
     private ServletConfig createServletConfig() {
         return new ServletConfigAdapter(filterConfig);
     }
 
 
     /***
      * Adapts a filter configuration object to become a servlet configuration
      * object.
      */
     class ServletConfigAdapter implements ServletConfig {
 
         /***
          * The filter configuration object to use.
          */
         private FilterConfig config;
 
 
         /***
          * Constructor.
          *
          * @param config The filter configuration object to use.
          */
         public ServletConfigAdapter(FilterConfig config) {
             this.config = config;
         }
 
         /*** {@inheritDoc} */
         public String getServletName() {
             return config.getFilterName();
         }
 
         /*** {@inheritDoc} */
         public ServletContext getServletContext() {
             return config.getServletContext();
         }
 
         /*** {@inheritDoc} */
         public String getInitParameter(String string) {
             return config.getInitParameter(string);
         }
 
         /*** {@inheritDoc} */
         @SuppressWarnings("unchecked")
         public Enumeration getInitParameterNames() {
             return config.getInitParameterNames();
         }
     }
 
 }