GoalToExecute.java

/* 
** Author(s): Miguel Calejo
** Contact:   interprolog@declarativa.com, http://www.declarativa.com
** Copyright (C) Declarativa, Portugal, 2000-2002
** Use and distribution, without any warranties, under the terms of the 
** GNU Library General Public License, readable in http://www.fsf.org/copyleft/lgpl.html
*/
package com.declarativa.interprolog.util;
import com.declarativa.interprolog.*;

public class GoalToExecute{
        private GoalFromJava goal;
        private ResultFromProlog result;
        private boolean executing;
        private boolean ended;
        private boolean firstGoalStatus = false;
        
        public GoalToExecute(GoalFromJava goal){
                this.goal = goal; 
                result=null; ended=false; executing=false;
        }
        
        public synchronized ResultFromProlog waitForResult(){
                if (ended) return result;
                System.out.println("---> Now it will hang here ....");
                try { wait();}
                catch(InterruptedException e){throw new IPException("Unexpected:"+e);}
                if (result==null) throw new IPException("Inconsistency in GoalToExecute");
                return result;
        }
        
        public synchronized void setResult(ResultFromProlog result){
                if (this.result!=null || hasEnded()) {
                        throw new IPException("Inconsistency in GoalToExecute");
                }
                this.result=result;
                ended=true;
                notify();
        }
        
        public boolean wasInterrupted(){
                return hasEnded() && "interrupted".equals(result.error);
        }

        public boolean wasAborted(){
                return hasEnded() && "aborted".equals(result.error);
        }

        public synchronized void interrupt(){
                raiseError("interrupted");
        }
        
        public synchronized void abort(){
                raiseError("aborted");
        }
        
        private void raiseError(String s){
                if (result==null) result = new ResultFromProlog(-1,false,0,null);
                result.error=s;
                ended=true;
                notify();
        }
        
        public GoalFromJava getGoal(){ return goal;}
        
        public void prologWasCalled(){
                if (executing) throw new IPException("Bad use of prologWasCalled");
                executing=true;
        }
        
        public boolean hasStarted(){
                return executing;
        }
        
        public boolean hasEnded(){
                return ended;
        }
        
        public int getTimestamp(){return goal.timestamp;}
        
        public void setFirstGoalStatus(){
                firstGoalStatus = true;
        }
        
        public boolean isFirstGoal(){
                return firstGoalStatus;
        }
        
        public String toString(){
                return "ResultFromProlog: timestamp=="+getTimestamp();
        }
}

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