org/sonews/daemon/AbstractDaemon.java
changeset 2 1090e2141798
child 3 2fdc9cc89502
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/org/sonews/daemon/AbstractDaemon.java	Wed Jul 01 10:48:22 2009 +0200
     1.3 @@ -0,0 +1,105 @@
     1.4 +/*
     1.5 + *   SONEWS News Server
     1.6 + *   see AUTHORS for the list of contributors
     1.7 + *
     1.8 + *   This program is free software: you can redistribute it and/or modify
     1.9 + *   it under the terms of the GNU General Public License as published by
    1.10 + *   the Free Software Foundation, either version 3 of the License, or
    1.11 + *   (at your option) any later version.
    1.12 + *
    1.13 + *   This program is distributed in the hope that it will be useful,
    1.14 + *   but WITHOUT ANY WARRANTY; without even the implied warranty of
    1.15 + *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    1.16 + *   GNU General Public License for more details.
    1.17 + *
    1.18 + *   You should have received a copy of the GNU General Public License
    1.19 + *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
    1.20 + */
    1.21 +
    1.22 +package org.sonews.daemon;
    1.23 +
    1.24 +import java.sql.SQLException;
    1.25 +import org.sonews.daemon.storage.Database;
    1.26 +import org.sonews.util.Log;
    1.27 +
    1.28 +/**
    1.29 + * Base class of all sonews threads.
    1.30 + * Instances of this class will be automatically registered at the ShutdownHook
    1.31 + * to be cleanly exited when the server is forced to exit.
    1.32 + * @author Christian Lins
    1.33 + * @since sonews/0.5.0
    1.34 + */
    1.35 +public abstract class AbstractDaemon extends Thread
    1.36 +{
    1.37 +
    1.38 +  /** This variable is write synchronized through setRunning */
    1.39 +  private boolean isRunning = false;
    1.40 +
    1.41 +  /**
    1.42 +   * Protected constructor. Will be called by derived classes.
    1.43 +   */
    1.44 +  protected AbstractDaemon()
    1.45 +  {
    1.46 +    setDaemon(true); // VM will exit when all threads are daemons
    1.47 +    setName(getClass().getSimpleName());
    1.48 +  }
    1.49 +  
    1.50 +  /**
    1.51 +   * @return true if shutdown() was not yet called.
    1.52 +   */
    1.53 +  public boolean isRunning()
    1.54 +  {
    1.55 +    synchronized(this)
    1.56 +    {
    1.57 +      return this.isRunning;
    1.58 +    }
    1.59 +  }
    1.60 +  
    1.61 +  /**
    1.62 +   * Marks this thread to exit soon. Closes the associated Database connection
    1.63 +   * if available.
    1.64 +   * @throws java.sql.SQLException
    1.65 +   */
    1.66 +  void shutdownNow()
    1.67 +    throws SQLException
    1.68 +  {
    1.69 +    synchronized(this)
    1.70 +    {
    1.71 +      this.isRunning = false;
    1.72 +      Database db = Database.getInstance(false);
    1.73 +      if(db != null)
    1.74 +      {
    1.75 +        db.shutdown();
    1.76 +      }
    1.77 +    }
    1.78 +  }
    1.79 +  
    1.80 +  /**
    1.81 +   * Calls shutdownNow() but catches SQLExceptions if occurring.
    1.82 +   */
    1.83 +  public void shutdown()
    1.84 +  {
    1.85 +    try
    1.86 +    {
    1.87 +      shutdownNow();
    1.88 +    }
    1.89 +    catch(SQLException ex)
    1.90 +    {
    1.91 +      Log.msg(ex, true);
    1.92 +    }
    1.93 +  }
    1.94 +  
    1.95 +  /**
    1.96 +   * Starts this daemon.
    1.97 +   */
    1.98 +  @Override
    1.99 +  public void start()
   1.100 +  {
   1.101 +    synchronized(this)
   1.102 +    {
   1.103 +      this.isRunning = true;
   1.104 +    }
   1.105 +    super.start();
   1.106 +  }
   1.107 +  
   1.108 +}