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/*
    This file is part of JLog.

    Created by Glendon Holst for Alan Mackworth and the 
    "Computational Intelligence: A Logical Approach" text.
    
    Copyright 1998, 2000, 2002 by University of British Columbia and 
    Alan Mackworth.
    
    This notice must remain in all files which belong to, or are derived 
    from JLog.
    
    Check  or 
     for further information
    about JLog, or to contact the authors.
     
    JLog 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 2 of the License, or
    (at your option) any later version.

    JLog 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 JLog; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    URLs:  or 
*/
//#########################################################################
//	jPrologServiceThread
//#########################################################################

package ubc.cs.JLog.Foundation;

import java.lang.*;
import java.util.*;

/**
* This class provides an independant thread of execution for services using 
* a jPrologService Prolog proof engine.
*
* @author       Glendon Holst
* @version      %I%, %G%
*/
public class jPrologServiceThread extends Thread
{
 protected jPrologServices 			prolog;
 protected jPrologServiceBroadcaster 		stopped = null;

 protected boolean 				allow_release;
 
 public 	jPrologServiceThread(jPrologServices ps)
 {
  prolog = ps;
  allow_release = true;
 };

 public jPrologServices 		getPrologServices()
 {
  return prolog;
 };
 
 public void 		setStoppedListeners(jPrologServiceBroadcaster s)
 {
  stopped = s;
 };

 // this is a bit of a hack (but stop() is final method).  there is no guarentee that
 // other broadcasted messages (such as end messages) from the run method have already 
 // been sent.
 public void 	broadcasted_stop()
 {
  if (stopped != null)
   stopped.broadcastEvent(new jThreadStoppedEvent(this));

  stop();
 };
 
 public boolean 	isCurrentlyConsulting()
 {
  return false;
 };

/**
* Set the thread release state upon completion.  By default the thread may
* release itself from jPrologServices when it no longer needs to
* use its services.  If this thread is being used in sequence (i.e., is
* being invoked by another worker thread) then it should not initiate release,
* because the next thread may need Prolog Services.
* 
* @param a 		true to allow thread release, false to disallow it. 
*/
 public void 		setAllowRelease(boolean a)
 {
  allow_release = a;
 };

 public void 		printOutput(String s)
 {
  prolog.printOutput(s);
 };
};