Oops! Yes, James and Ernest are correct... an error of omission on my part. You do indeed need to override the hashCode() method, too.
I was fortunate enough to win a copy of Thinking in Java 3rd ed by Bruce Eckles at my local Java users group. It is available *free* as an electronic book at http://mindview.net/Books/DownloadSites . If you look at Chapter 11: Hashing and Hash Codes you will find the complete example that James mentioned. Just remember that, by default, equals() only compares object references -- for anything else you have to write a custom implementation. Cheers, -JM ------------------------ Jason Morris Morris Technical Solutions [EMAIL PROTECTED] www.morristechnicalsolutions.com fax/phone: 503.692.1088 > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Behalf Of [EMAIL PROTECTED] > Sent: Tuesday, August 03, 2004 12:42 PM > To: [EMAIL PROTECTED] > Subject: Re: JESS: new to jess > > > I think James Owen wrote: > > One other thing, something that most "old timers" even forget. :-) If > > you re-write equals for a class that already exists or one that you > > inherit then you have to re-write the hash map table. > > Of course what jco means is that if you override equals(), you should > override hashCode() as well; the details of doing this correctly are > spelled out quite clearly in the Javadocs for the Object class. Joshua > Bloch's book is, indeed, good as well. > > > > --------------------------------------------------------- > Ernest Friedman-Hill > Advanced Software Research Phone: (925) 294-2154 > Sandia National Labs FAX: (925) 294-2234 > PO Box 969, MS 9012 [EMAIL PROTECTED] > Livermore, CA 94550 http://herzberg.ca.sandia.gov > > -------------------------------------------------------------------- > To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' > in the BODY of a message to [EMAIL PROTECTED], NOT to the list > (use your own address!) List problems? Notify [EMAIL PROTECTED] > -------------------------------------------------------------------- > -------------------------------------------------------------------- To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list (use your own address!) List problems? Notify [EMAIL PROTECTED] --------------------------------------------------------------------
