# JobProcessor.java

    /*
    ** Module   : JobProcessor.java
    ** Abstract : Concrete job launcher, which listens for jobs posted via the timer thread and
    **            executes them.
    **
    ** Copyright (c) 2014-2023, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ---------------------------------Description----------------------------------
    ** 001 CA  20140206 First version.
    ** 002 CA  20140220 Fixed a bug in the job waiting loop - wait only if there are no pending jobs.
    ** 003 CA  20170228 Moved Scheduler.initialize to Scheduler.scheduleJobs.
    ** 004 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
    ** 005 GBB 20230620 createThreadName method moved to Utils.
    */
    /*
    ** This program is free software: you can redistribute it and/or modify
    ** it under the terms of the GNU Affero 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 Affero General Public License for more details.
    **
    ** You may find a copy of the GNU Affero GPL version 3 at the following
    ** location: https://www.gnu.org/licenses/agpl-3.0.en.html
    **
    ** Additional terms under GNU Affero GPL version 3 section 7:
    **
    **   Under Section 7 of the GNU Affero GPL version 3, the following additional
    **   terms apply to the works covered under the License.  These additional terms
    **   are non-permissive additional terms allowed under Section 7 of the GNU
    **   Affero GPL version 3 and may not be removed by you.
    **
    **   0. Attribution Requirement.
    **
    **     You must preserve all legal notices or author attributions in the covered
    **     work or Appropriate Legal Notices displayed by works containing the covered
    **     work.  You may not remove from the covered work any author or developer
    **     credit already included within the covered work.
    **
    **   1. No License To Use Trademarks.
    **
    **     This license does not grant any license or rights to use the trademarks
    **     Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
    **     of Golden Code Development Corporation. You are not authorized to use the
    **     name Golden Code, FWD, or the names of any author or contributor, for
    **     publicity purposes without written authorization.
    **
    **   2. No Misrepresentation of Affiliation.
    **
    **     You may not represent yourself as Golden Code Development Corporation or FWD.
    **
    **     You may not represent yourself for publicity purposes as associated with
    **     Golden Code Development Corporation, FWD, or any author or contributor to
    **     the covered work, without written authorization.
    **
    **   3. No Misrepresentation of Source or Origin.
    **
    **     You may not represent the covered work as solely your work.  All modified
    **     versions of the covered work must be marked in a reasonable way to make it
    **     clear that the modified work is not originating from Golden Code Development
    **     Corporation or FWD.  All modified versions must contain the notices of
    **     attribution required in this license.
    */

    package com.goldencode.p2j.scheduler;

    import java.util.*;

    import com.goldencode.p2j.net.*;
    import com.goldencode.p2j.security.*;
    import com.goldencode.p2j.util.*;

    /**
     * Specialized class which listens for incoming jobs (sent by the {@link Scheduler#timer}.
     * This class runs in a separate thread, under the server's context.
     */
    class JobProcessor
    implements Runnable
    {
       /** The list with the pending jobs. */
       private final LinkedList<Runnable> pendingJobs = new LinkedList<>();

       /**
        * Initialize the scheduler and schedule the initial jobs.  Then, start listening for new
        * jobs being posted to the {@link #pendingJobs queue} by the {@link Scheduler#timer}.
        */
       @Override
       public void run()
       {
          // before starting, wait for the server to start listening
          try
          {
             SessionManager.get().waitUntilReady();
          }
          catch (InterruptedException e)
          {
             return;
          }

          // add initial jobs
          synchronized (Scheduler.jobs)
          {
             for (Job job : Scheduler.jobs.values())
             {
                if (!job.isEnabled())
                {
                   // skip disabled jobs
                   continue;
                }

                Scheduler.scheduleJob(job.getName(), null);
             }
          }

          Runnable core = null;

          // listen for incoming jobs
          while (true)
          {
             synchronized (pendingJobs)
             {
                if (pendingJobs.isEmpty())
                {
                   try
                   {
                      pendingJobs.wait();
                   }
                   catch (InterruptedException e)
                   {
                      // someone interrupted me, exit
                      break;
                   }
                }

                core = (pendingJobs.isEmpty()) ? null : pendingJobs.removeFirst();
             }

             if (core != null)
             {
                // execute this in a different thread, but with the server's context
                Thread t = new AssociatedThread(core);
                String tname = Utils.createThreadName(String.format(core.toString()));
                t.setDaemon(true);
                t.setName(tname);
                t.start();
             }
          }
       }

       /**
        * Execute the given job.
        *
        * @param    core
        *           The {@link Runnable} instance to execute the job.
        */
       public void executeJob(Runnable core)
       {
          synchronized (pendingJobs)
          {
             pendingJobs.addLast(core);
             pendingJobs.notify();
          }
       }
    }