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    * Licensed to the Apache Software Foundation (ASF) under one   *
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    * 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   *
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   *   http://www.apache.org/licenses/LICENSE-2.0                 *
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   * software distributed under the License is distributed on an  *
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
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   * specific language governing permissions and limitations      *
   * under the License.                                           *
   ****************************************************************/
  
  
   
  package org.apache.james.fetchmail;
  
  import java.util.ArrayList;
  import java.util.Iterator;
  
  import org.apache.avalon.cornerstone.services.scheduler.PeriodicTimeTrigger;
  import org.apache.avalon.cornerstone.services.scheduler.TimeScheduler;
  import org.apache.avalon.framework.activity.Disposable;
  import org.apache.avalon.framework.activity.Initializable;
  import org.apache.avalon.framework.configuration.Configurable;
  import org.apache.avalon.framework.configuration.Configuration;
  import org.apache.avalon.framework.configuration.ConfigurationException;
  import org.apache.avalon.framework.container.ContainerUtil;
  import org.apache.avalon.framework.logger.AbstractLogEnabled;
  import org.apache.avalon.framework.service.ServiceException;
  import org.apache.avalon.framework.service.ServiceManager;
  import org.apache.avalon.framework.service.Serviceable;
  
  /**
   *  A class to instantiate and schedule a set of mail fetching tasks
   *
   * $Id: FetchScheduler.java 521427 2007-03-22 19:57:00Z bago $
   *
   */
  public class FetchScheduler
      extends AbstractLogEnabled
      implements Serviceable, Configurable, Initializable, Disposable, FetchSchedulerMBean {
  
      /**
       * Configuration object for this service
       */
      private Configuration conf;
  
      /**
       * The service manager that allows access to the system services
       */
      private ServiceManager m_manager;
  
      /**
       * The scheduler service that is used to trigger fetch tasks.
       */
      private TimeScheduler scheduler;
  
      /**
       * Whether this service is enabled.
       */
      private volatile boolean enabled = false;
  
      private ArrayList theFetchTaskNames = new ArrayList();
  
      public void setScheduler(TimeScheduler scheduler) {
          this.scheduler = scheduler;
      }
  
      /**
       * @see org.apache.avalon.framework.service.Serviceable#service( ServiceManager )
       */
      public void service(ServiceManager comp) throws ServiceException
      {
          m_manager = comp;
      }
  
      /**
       * @see org.apache.avalon.framework.configuration.Configurable#configure(Configuration)
       */
      public void configure(Configuration conf) throws ConfigurationException
      {
          this.conf = conf;
      }
  
      /**
       * @see org.apache.avalon.framework.activity.Initializable#initialize()
       */
      public void initialize() throws Exception
      {
          enabled = conf.getAttributeAsBoolean("enabled", false);
          if (enabled)
          {
             TimeScheduler scheduler = (TimeScheduler) m_manager.lookup(TimeScheduler.ROLE);
             setScheduler(scheduler);
 
             Configuration[] fetchConfs = conf.getChildren("fetch");
             for (int i = 0; i < fetchConfs.length; i++)
             {
                 // read configuration
                 Configuration fetchConf = fetchConfs[i];
                 String fetchTaskName = fetchConf.getAttribute("name");
                 Integer interval = new Integer(fetchConf.getChild("interval").getValue());
 
                 FetchMail fetcher = new FetchMail();
                 
                 // avalon specific initialization
                 ContainerUtil.enableLogging(fetcher,getLogger().getChildLogger(fetchTaskName));
                 ContainerUtil.service(fetcher,m_manager);
                 ContainerUtil.configure(fetcher,fetchConf);
 
                 // initialize scheduling
                 PeriodicTimeTrigger fetchTrigger =
                         new PeriodicTimeTrigger(0, interval.intValue());
                 scheduler.addTrigger(fetchTaskName, fetchTrigger, fetcher);
                 theFetchTaskNames.add(fetchTaskName);
             }
 
             if (getLogger().isInfoEnabled()) getLogger().info("FetchMail Started");
             System.out.println("FetchMail Started");
         }
         else
         {
             if (getLogger().isInfoEnabled()) getLogger().info("FetchMail Disabled");
             System.out.println("FetchMail Disabled");
         }
     }
 
     /**
      * @see org.apache.avalon.framework.activity.Disposable#dispose()
      */
     public void dispose()
     {
         if (enabled)
         {
             getLogger().info("FetchMail dispose...");
             Iterator nameIterator = theFetchTaskNames.iterator();
             while (nameIterator.hasNext())
             {
                 scheduler.removeTrigger((String) nameIterator.next());
             }
             getLogger().info("FetchMail ...dispose end");
         }
     }
     
     /**
      * Describes whether this service is enabled by configuration.
      *
      * @return is the service enabled.
      */
     public final boolean isEnabled() {
         return enabled;
     }
     
 }