content: /*
   * This library is part of OpenCms -
   * the Open Source Content Management System
   *
   * Copyright (c) Alkacon Software GmbH & Co. KG (https://www.alkacon.com)
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library 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
   * Lesser General Public License for more details.
   *
   * For further information about Alkacon Software GmbH & Co. KG, please see the
   * company website: https://www.alkacon.com
   *
   * For further information about OpenCms, please see the
   * project website: https://www.opencms.org
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  package org.opencms.scheduler;
  
  import org.opencms.main.CmsLog;
  
  import org.apache.commons.logging.Log;
  
  /**
   * A worker thread for the OpenCms scheduler.<p>
   *
   * @since 6.0.0
   */
  public class CmsSchedulerThread extends Thread {
  
      /** The log object for this class. */
      private static final Log LOG = CmsLog.getLog(CmsSchedulerThread.class);
  
      /** The scheduler thread pool this thread belongs to. */
      private CmsSchedulerThreadPool m_pool;
  
      /** A flag that signals the thread to terminate. */
      private boolean m_run;
  
      /** A runnable class. */
      private Runnable m_runnable;
  
      /**
       * Create a scheduler thread that runs continuosly,
       * waiting for new runnables to be provided by the scheduler thread pool.<p>
       *
       * @param pool the pool to use
       * @param threadGroup the thread group to use
       * @param threadName the name for the thread
       * @param prio the priority of the thread
       * @param isDaemon controls if this should be a deamon thread or not
       */
      CmsSchedulerThread(
          CmsSchedulerThreadPool pool,
          ThreadGroup threadGroup,
          String threadName,
          int prio,
          boolean isDaemon) {
  
          this(pool, threadGroup, threadName, prio, isDaemon, null);
      }
  
      /**
       * Create a scheduler thread that runs the specified runnable exactly once.<p>
       *
       * @param pool the pool to use
       * @param threadGroup the thread group to use
       * @param threadName the name for the thread
       * @param prio the priority of the thread
       * @param isDaemon controls if this should be a deamon thread or not
       * @param runnable the runnable to run
       */
      CmsSchedulerThread(
          CmsSchedulerThreadPool pool,
          ThreadGroup threadGroup,
          String threadName,
          int prio,
          boolean isDaemon,
          Runnable runnable) {
  
          super(threadGroup, threadName);
          m_run = true;
          m_pool = pool;
          m_runnable = runnable;
          setPriority(prio);
          setDaemon(isDaemon);
      }
  
      /**
       * Loop, executing targets as they are received.<p>
       */
      @Override
      public void run() {
  
          boolean runOnce = (m_runnable != null);
  
          while (m_run) {
              setPriority(m_pool.getThreadPriority());
              try {
                  if (m_runnable == null) {
                      m_runnable = m_pool.getNextRunnable();
                  }
  
                  if (m_runnable != null) {
                      m_runnable.run();
                  }
              } catch (InterruptedException e) {
                  LOG.error(Messages.get().getBundle().key(Messages.LOG_THREAD_INTERRUPTED_1, getName()), e);
              } catch (Throwable t) {
                  LOG.error(Messages.get().getBundle().key(Messages.LOG_THREAD_ERROR_1, getName()), t);
              } finally {
                  if (runOnce) {
                      m_run = false;
                  }
                  m_runnable = null;
              }
          }
          if (LOG.isDebugEnabled()) {
              LOG.debug(Messages.get().getBundle().key(Messages.LOG_THREAD_SHUTDOWN_1, getName()));
          }
      }
  
      /**
       * Signal the thread that it should terminate.<p>
       */
      void shutdown() {
  
          m_run = false;
      }
  }