/*
    * 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.jetspeed.scheduler;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.commons.configuration.Configuration;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  /***
   * Service for a cron like scheduler that uses the
   * properties file instead of the database.
   * The methods that operate on jobs ( get,add,update,remove )
   * only operate on the queue in memory and changes are not reflected
   * to the properties file which was used to initilize the jobs.
   * An example is given below.  The job names are the class names that
   * extend ScheduledJob.
   *
   * <PRE>
   *
   * services.SchedulerService.scheduler.jobs=scheduledJobName,scheduledJobName2
   *
   * services.SchedulerService.scheduler.job.scheduledJobName.ID=1
   * services.SchedulerService.scheduler.job.scheduledJobName.SECOND=-1
   * services.SchedulerService.scheduler.job.scheduledJobName.MINUTE=-1
   * services.SchedulerService.scheduler.job.scheduledJobName.HOUR=7
   * services.SchedulerService.scheduler.job.scheduledJobName.WEEKDAY=-1
   * services.SchedulerService.scheduler.job.scheduledJobName.DAY_OF_MONTH=-1
   *
   * services.SchedulerService.scheduler.job.scheduledJobName2.ID=1
   * services.SchedulerService.scheduler.job.scheduledJobName2.SECOND=-1
   * services.SchedulerService.scheduler.job.scheduledJobName2.MINUTE=-1
   * services.SchedulerService.scheduler.job.scheduledJobName2.HOUR=7
   * services.SchedulerService.scheduler.job.scheduledJobName2.WEEKDAY=-1
   * services.SchedulerService.scheduler.job.scheduledJobName2.DAY_OF_MONTH=-1
   *
   * </PRE>
   *
   * Based on TamboraSchedulerService written by John Thorhauer.
   *
   * @author <a href="mailto:ekkerbj@netscpae.net">Jeff Brekke</a>
   * @author <a href="mailto:john@zenplex.com">John Thorhauer</a>
   * @author <a href="mailto:taylor@apache.org">David Sean Taylor</a>
   * @version $Id: MemoryBasedScheduler.java 516448 2007-03-09 16:25:47Z ate $
   */
  public class MemoryBasedScheduler
      extends AbstractScheduler implements Scheduler
  {
      private final static Log log = LogFactory.getLog(MemoryBasedScheduler.class);
      private Configuration config;
      
      /***
       * Constructor.
       *
       * @exception Exception, a generic exception.
       */
      public MemoryBasedScheduler(Configuration config)
          throws Exception
      {
          super();
          this.config = config;
      }
  
      private Configuration getConfiguration()
      {
          return config;
      }
      
      public void start()
      {
          try
          {            
              super.start();
              scheduleQueue = new JobQueue();
              mainLoop = new MainLoop();
  
              List jobProps = getConfiguration().getList("jobs");            
              List jobs = new ArrayList();
              // If there are scheduler.jobs defined then set up a job vector
              // for the scheduleQueue
              if (!jobProps.isEmpty())
              {
                  for (int i=0;i<jobProps.size();i++)
                 {
                     String jobName = (String)jobProps.get(i);
                     String jobPrefix = "job." + jobName ;
 
                     if ( (getConfiguration().getString(jobPrefix + ".ID", null)) == null)
                     {
                         throw new Exception(
                         "There is an error in the properties file. \n" +
                         jobPrefix + ".ID is not found.\n");
                     }
 
                     int sec =  getConfiguration().getInt(jobPrefix + ".SECOND", -1);
                     int min =  getConfiguration().getInt(jobPrefix + ".MINUTE", -1);
                     int hr  =  getConfiguration().getInt(jobPrefix + ".HOUR", -1);
                     int wkday =  getConfiguration().getInt(jobPrefix + ".WEEKDAY", -1);
                     int dayOfMonth =  getConfiguration().getInt(jobPrefix + ".DAY_OF_MONTH", -1);
 
                     JobEntry je = new JobEntry(
                         sec,
                         min,
                         hr,
                         wkday,
                         dayOfMonth,
                         jobName);
 
                     jobs.add(je);
 
                 }
             }
 
             if ( jobs != null && jobs.size() > 0 )
             {
 //                System.out.println("Starting jobs = " + jobs.size());            
                 
                 scheduleQueue.batchLoad(jobs);
                 restart();
             }
 
         }
         catch (Exception e)
         {
             log.error ("Cannot initialize SchedulerService!: ", e);
         }
          
     }
     
     public void stop()
     {
         super.stop();
     }
 
     /***
      * This method returns the job element from the internal queue.
      *
      * @param oid The int id for the job.
      * @return A JobEntry.
      * @exception Exception, a generic exception.
      */
     public JobEntry getJob(int oid)
         throws Exception
     {
         JobEntry je = new JobEntry(-1,
                                    -1,
                                    -1,
                                    -1,
                                    -1,
                                    null);
         return scheduleQueue.getJob(je);
     }
 
     /***
      * Add a new job to the queue.
      *
      * @param je A JobEntry with the job to add.
      * @exception Exception, a generic exception.
      */
     public void addJob(JobEntry je)
         throws Exception
     {
         // Add to the queue.
         scheduleQueue.add(je);
         restart();
     }
 
     /***
      * Remove a job from the queue.
      *
      * @param je A JobEntry with the job to remove.
      * @exception Exception, a generic exception.
      */
     public void removeJob(JobEntry je)
         throws Exception
     {
         // Remove from the queue.
         scheduleQueue.remove(je);
         restart();
     }
 
     /***
      * Modify a Job.
      *
      * @param je A JobEntry with the job to modify
      * @exception Exception, a generic exception.
      */
     public void updateJob(JobEntry je)
         throws Exception
     {
         try
         {
             je.calcRunTime();
         }
         catch(Exception e)
         {
             // Log problems.
             log.error("Problem updating Scheduled Job: " + e);
         }
         // Update the queue.
        scheduleQueue.modify(je);
        restart();
     }
 }