The only thing here that's clearly wrong is the equals() method -- you
can't (generally) compare Strings with equals -- you want to use the
equals() method instead. But otherwise from Jess's perspective I think
things should be fine.
How are you adding the objects to working memory? Using "add" or
"definstance"? Can I see that line of code?
On Aug 21, 2009, at 11:20 AM, Pierre Bezuhov wrote:
When I call firePropertyChange from my Java object after setting an
attribute the working memory of my engine is not updated. I know
this because I loop through the facts before and after the setting
of the attribute, and "round" is set to "0" both times.
My Java and Jess code is below (if you're wondering why I have a
class just to wrap an int and string, it's to tie into some 3rd
party code I don't have control over). Any idea what I'm doing wrong?
######## JAVA CLASS ########
package game.server;
import java.beans.*;
import java.io.*;
import java.nio.*;
import java.util.*;
import jess.*;
public class Round implements Serializable
{
private static final long serialVersionUID = 1L;
private int round;
private String gameName;
private PropertyChangeSupport propertyChange;
protected Round(int round, String game)
{
this.round = round;
gameName = game;
propertyChange = new PropertyChangeSupport(this);
}
public int getRound()
{
return round;
}
public void setRound(int round)
{
if (this.round != round)
{
int oldValue = this.round;
this.round = round;
// Fire property change event so Jess working memory is
updated
propertyChange.firePropertyChange("round", new
Integer(oldValue), new Integer(this.round));
}
}
public String getGameName()
{
return gameName;
}
public void setGameName(String game)
{
gameName = game;
}
public void addPropertyChangeListener(PropertyChangeListener
listener)
{
propertyChange.addPropertyChangeListener(listener);
}
public void removePropertyChangeListener(PropertyChangeListener
listener)
{
propertyChange.removePropertyChangeListener(listener);
}
public boolean equals(Object obj)
{
boolean equal = false;
if (obj instanceof Round)
{
Round objRound = (Round)obj;
equal = ((objRound.getRound() == round) &&
(objRound.getGameName() == gameName));
}
return equal;
}
public int hashCode()
{
// Game name never changes so hashCode is mutable
return gameName.hashCode();
}
}
######## JESS RULES ########
(import game.server.*)
(deftemplate Round (declare (from-class Round)))
(defrule process-round
(Round {round >= 0} (round ?round))
=>
(printout t "Round " ?round crlf)
)
---------------------------------------------------------
Ernest Friedman-Hill
Informatics & Decision Sciences, Sandia National Laboratories
PO Box 969, MS 9012, Livermore, CA 94550
http://www.jessrules.com
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