/*

  *   SONEWS News Server

  *   see AUTHORS for the list of contributors

  *

  *   This program is free software: you can redistribute it and/or modify

  *   it under the terms of the GNU General Public License as published by

  *   the Free Software Foundation, either version 3 of the License, or

  *   (at your option) any later version.

  *

  *   This program is distributed in the hope that it will be useful,

  *   but WITHOUT ANY WARRANTY; without even the implied warranty of

  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  *   GNU General Public License for more details.

  *

  *   You should have received a copy of the GNU General Public License

  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.

  */

 package org.sonews.daemon;

 import java.sql.SQLException;

 import org.sonews.daemon.storage.Database;

 import org.sonews.util.Log;

 /**

  * Base class of all sonews threads.

  * Instances of this class will be automatically registered at the ShutdownHook

  * to be cleanly exited when the server is forced to exit.

  * @author Christian Lins

  * @since sonews/0.5.0

  */

 public abstract class AbstractDaemon extends Thread

 {

   /** This variable is write synchronized through setRunning */

   private boolean isRunning = false;

   /**

    * Protected constructor. Will be called by derived classes.

    */

   protected AbstractDaemon()

   {

     setDaemon(true); // VM will exit when all threads are daemons

     setName(getClass().getSimpleName());

   }

   /**

    * @return true if shutdown() was not yet called.

    */

   public boolean isRunning()

   {

     synchronized(this)

     {

       return this.isRunning;

     }

   }

   /**

    * Marks this thread to exit soon. Closes the associated Database connection

    * if available.

    * @throws java.sql.SQLException

    */

   void shutdownNow()

     throws SQLException

   {

     synchronized(this)

     {

       this.isRunning = false;

       Database db = Database.getInstance(false);

       if(db != null)

       {

         db.shutdown();

       }

     }

   }

   /**

    * Calls shutdownNow() but catches SQLExceptions if occurring.

    */

   public void shutdown()

   {

     try

     {

       shutdownNow();

     }

     catch(SQLException ex)

     {

       Log.msg(ex, true);

     }

   }

   /**

    * Starts this daemon.

    */

   @Override

   public void start()

   {

     synchronized(this)

     {

       this.isRunning = true;

     }

     super.start();

   }

 }