ObjectRegistry.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 ObjectRegistry{
        private static final int MAXOBJECTS = 2000;
    private Object objectTable[] = new Object[MAXOBJECTS]; int nObjects=0;

        public Object getRealJavaObject(InvisibleObject o){
                return getRealJavaObject(o.ID);
        }
        
        public Object getRealJavaObject(int ID){
                if (ID<0 | ID>nObjects-1) 
                        throw new RuntimeException("Bad object ID in ObjectRegistry");
                return objectTable[ID];
        }
        
        public int registerJavaObject(Object x){
                int i = getObjectID(x);
                if (i>=0) return i;
                if (nObjects>=MAXOBJECTS) 
                        throw new IPException("Too many Java objects in ObjectRegistry");
                if (x==null)
                        throw new IPException("Null object in ObjectRegistry");
                objectTable[nObjects++] = x;
                return nObjects-1;
        }
        
        private int getObjectID(Object x){
                int i = 0;
                while (i<nObjects)
                        if (objectTable[i]==x) return i;
                        else i++;
                return -1;
        }
}

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