What do you call this basic technique?

Question

Request: Is there a name for the technique I'm using below, because I
know I've seen it and done it before.
Context: I'd like to allow the user to resize images, while preserving
their width:height aspect ratio. My GUI has a pair of JSpinners, for width
and height, and when one is adjusted, the other should change.
Example: if the aspect ratio is 2:1, setting the width spinner to 201
should cause the height spinner to change to 100 (I truncate), whilst setting
the height spinner to 100 should cause the width spinner to change to 200.
But: I don't want those reactions to cascade: from the example, if the
user sets the width spinner to 201, the height spinner should change to 100,
but that is where it should stop -- the width spinner shouldn't itself react
and change to 200.
My solution: I'm a fan of fixing it in the model, and here is my tweak for
SpinnerNumberModel: public class SafeSpinnerNumberModel extends SpinnerNumberModel {
     public SafeSpinnerNumberModel(int value, int minimum, int maximum, int stepSize) {
         super(value, minimum, maximum, stepSize);
     public void setValue(Object value) {
         if (!inSetValue) {
             inSetValue = true;
             super.setValue(value);
             inSetValue = false;
     private boolean inSetValue;
In my code, there are two JSpinners (with SafeSpinnerNumberModels),
and each model has a ChangeListener that reacts by adjusting the other model.
The flag stops the potential feedback loop.
So, again, what would you call this technique?
Thanks,
BDLH

Answer 1

Me too. And they love all those visual little
thingies so much: ooh, when
the number is positive it's displayed in black,
otherwise it's red. I'm a
genius! No lemme put 90 percent profit in here, just
for the "what-if"
question part. Yay! It's black!You should see some of the spreadhseets we have here. Risk management, process compliance, earned value management... I have no idea what any of this is, but its all thousands of rows of red-green-yellow, telling who's not doing any work. And if you change one value all the colors change all over the place. I bet they have Tetris encoded in there.
I attempted to finish my bookkeeping for Q3 last
Sunday but I was
distracted by myself attempting to do the Towers of
Hanoi puzzle
using Excel. I managed to make it work, but it was so
awful (using
additional cells etc) I deleted it all. I still have
to finish up Q3 ...Hmm, I believe I'll start short-selling JosAH Industries ;-)