package org.apache.commons.jcs.admin.servlet;
   
   /*
    * 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.
   */
  
  import org.apache.commons.jcs.admin.JCSAdminBean;
  import org.apache.velocity.Template;
  import org.apache.velocity.context.Context;
  import org.apache.velocity.tools.view.VelocityViewServlet;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import java.io.IOException;
  
  /**
   * A servlet which provides HTTP access to JCS. Allows a summary of regions to
   * be viewed, and removeAll to be run on individual regions or all regions. Also
   * provides the ability to remove items (any number of key arguments can be
   * provided with action 'remove'). Should be initialized with a properties file
   * that provides at least a classpath resource loader. Since this extends
   * VelocityServlet, which uses the singleton model for velocity, it will share
   * configuration with any other Velocity in the same JVM.
   * <p>
   * Initialization in a webapp will look something like this:
   * <p>
   *
   * <pre>
   *
   *    [servlet]
   *        [servlet-name]JCSAdminServlet[/servlet-name]
   *        [servlet-class]org.apache.commons.jcs.admin.servlet.JCSAdminServlet[/servlet-class]
   *        [init-param]
   *            [param-name]properties[/param-name]
   *            [param-value]WEB-INF/conf/JCSAdminServlet.velocity.properties[/param-value]
   *        [/init-param]
   *    [/servlet]
   *
   * </pre>
   *
   * <p>
   * FIXME: It would be nice to use the VelocityEngine model so this can be truly
   * standalone. Right now if you run it in the same container as, say, turbine,
   * turbine must be run first to ensure it's config takes precedence.
   * <p>
   */
  public class JCSAdminServlet
      extends VelocityViewServlet
  {
      private static final long serialVersionUID = -5519844149238645275L;
  
      private static final String DEFAULT_TEMPLATE_NAME = "/org/apache/jcs/admin/servlet/JCSAdminServletDefault.vm";
  
      private static final String REGION_DETAIL_TEMPLATE_NAME = "/org/apache/jcs/admin/servlet/JCSAdminServletRegionDetail.vm";
  
      // Keys for parameters
  
      private static final String CACHE_NAME_PARAM = "cacheName";
  
      private static final String ACTION_PARAM = "action";
  
      private static final String KEY_PARAM = "key";
  
      private static final String SILENT_PARAM = "silent";
  
      // Possible values for 'action' parameter
  
      private static final String CLEAR_ALL_REGIONS_ACTION = "clearAllRegions";
  
      private static final String CLEAR_REGION_ACTION = "clearRegion";
  
      private static final String REMOVE_ACTION = "remove";
  
      private static final String DETAIL_ACTION = "detail";
  
      /**
       * Velocity based admin servlet.
       * <p>
       * @param request
       * @param response
       * @param context
       * @return Template
       *
       */
     @Override
     protected Template handleRequest( HttpServletRequest request, HttpServletResponse response, Context context )
     {
         JCSAdminBean admin = new JCSAdminBean();
 
         String templateName = DEFAULT_TEMPLATE_NAME;
 
         // Get cacheName for actions from request (might be null)
 
         String cacheName = request.getParameter( CACHE_NAME_PARAM );
 
         // If an action was provided, handle it
 
         String action = request.getParameter( ACTION_PARAM );
 
         try
         {
 			if ( action != null )
 			{
 			    if ( action.equals( CLEAR_ALL_REGIONS_ACTION ) )
 			    {
 			        admin.clearAllRegions();
 			    }
 			    else if ( action.equals( CLEAR_REGION_ACTION ) )
 			    {
 			        if ( cacheName != null )
 			        {
 			            admin.clearRegion( cacheName );
 			        }
 			    }
 			    else if ( action.equals( REMOVE_ACTION ) )
 			    {
 			        String[] keys = request.getParameterValues( KEY_PARAM );
 
 			        for ( int i = 0; i < keys.length; i++ )
 			        {
 			            admin.removeItem( cacheName, keys[i] );
 			        }
 
 			        templateName = REGION_DETAIL_TEMPLATE_NAME;
 			    }
 			    else if ( action.equals( DETAIL_ACTION ) )
 			    {
 			        templateName = REGION_DETAIL_TEMPLATE_NAME;
 			    }
 			}
 		}
         catch (IOException e)
         {
         	getLog().error("Could not execute action.", e);
         	return null;
 		}
 
         if ( request.getParameter( SILENT_PARAM ) != null )
         {
             // If silent parameter was passed, no output should be produced.
 
             return null;
         }
         // Populate the context based on the template
 
         try
         {
 			if ( templateName == REGION_DETAIL_TEMPLATE_NAME )
 			{
 			    context.put( "cacheName", cacheName );
 			    context.put( "elementInfoRecords", admin.buildElementInfo( cacheName ) );
 			}
 			else if ( templateName == DEFAULT_TEMPLATE_NAME )
 			{
 			    context.put( "cacheInfoRecords", admin.buildCacheInfo() );
 			}
 		}
         catch (Exception e)
         {
         	getLog().error("Could not populate context.", e);
 		}
 
         return getTemplate( templateName );
     }
 }