RE: Java: Using Comparable to Establish Natural Order
- From: "Adrian Beech" <a.beech@xxxxxxxxxxxxxx>
- To: <programmingblind@xxxxxxxxxxxxx>
- Date: Sat, 29 Nov 2008 13:11:48 +1000
G'day,
Chances are your getting odd behaviour because the signed int is not big
enough to cater for the difference between the two arbitrary doubles. A
safer way would be to return either -1, 0 or 1 depending on the comparisons
between the two calculated values.
For example:
Int result = 0;
If (val1 > val2) {
Result = 1;
}
Else if (val1 < val2) {
Result = -1;
}
Return result;
Change the 1 and -1 accordingly depending on the desired sort order.
Hope this helps.
Cheers.
AB
-----Original Message-----
From: programmingblind-bounce@xxxxxxxxxxxxx
[mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Jared Wright
Sent: Saturday, 29 November 2008 10:16 AM
To: programmingblind@xxxxxxxxxxxxx
Subject: Re: Java: Using Comparable to Establish Natural Order
Nope. Had migrated to other bits and pieces of code in the little bit of
time I had on Thanksgiving. Would still appreciate any thoughts or
suggestions you might have.
JW
Ken Perry wrote:
> Did you get this working I am just now catching up with mail.
>
> Ken
>
> -----Original Message-----
> From: programmingblind-bounce@xxxxxxxxxxxxx
> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Jared Wright
> Sent: Thursday, November 27, 2008 12:28 PM
> To: programmingblind@xxxxxxxxxxxxx
> Subject: Java: Using Comparable to Establish Natural Order
>
> Hi all, I've used comparable before, but with this go 'round I have
> found I must be missing something. I'm trying to use Comparable to
> establish the natural order of an Item class. Each item has a cost,
> size, and with these two values, the "value" of the item can be
> calculated. I wish for this value metric to be the index for the items'
> natural ordering, so priority queues and collection sorting methods will
> use this to order item objects. With the below code, my items are all
> returned to me from a priority queue simply in the reverse order they
> were added to the queue. Suggestions aappreciated, and I'll give much
> thanks on this of all days for any help! *grin* I am trying to have it
> order items with highest values first.
>
> Best,
> JW
>
>
> // Class representing an item.
> class Item implements Comparable {
> private double cost=0; private double size=0;
> public Item(double dCost, double dSize) {
> cost = dCost;
> size = dSize;
> }
> public double getCost() {
> return cost;
> }
> public double getSize() {
> return size;
> }
> public double getValue() {
> return cost/size;
> }
> public int compareTo(Object oItem) {
> double oItemValue = ((Item)oItem).getValue();
> double result = ((this.getValue()))-oItemValue;
> return (int)result;
> }
> }
> __________
> View the list's information and change your settings at
> //www.freelists.org/list/programmingblind
>
> __________
> View the list's information and change your settings at
> //www.freelists.org/list/programmingblind
>
>
>
__________
View the list's information and change your settings at
//www.freelists.org/list/programmingblind
__________ NOD32 3650 (20081128) Information __________
This message was checked by NOD32 antivirus system.
http://www.eset.com
__________
View the list's information and change your settings at
//www.freelists.org/list/programmingblind
Other related posts:
