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Nomak · Guest

Hello,

let's say that i have a JTextField and a JSlider which enable the user to view the same number in different ways. I can't find a good way to synchronize both of the components.

Right now, i'm using property change events:

- one of the component view/controller is modified by the user
- a change listener is called, and it call the setter
- the setter change the attribute and fire a property change event
- the event i catched by a property change listener wich set the value to the JTextField (which start no event) and set the value of the jslider if it's not the same

the example here is simple to understand, but the real program have more data like that and i have some constraint which are hard to respect because of the synchronization problem:

- view/controller of A is modified
- a change listener call the setter of A
- the setter of A fire a change property event
- the event is catched by another listener
- the listener calculate the constraint and extrat B. Then it set all the view/controller of A, and then the ones of B.
- view/controller of B is modified
- ... almost infinite loop

Have you some pointers (articles, url, pdf) on how to handle this?

I would like to know what already exist before "making the wheel again".

TIA

Chris Smith · Guest

Nomak <none (AT) invalid (DOT) domain.fr> wrote:

Roedy Green · Guest

On Fri, 9 Sep 2005 16:23:27 +0200, Nomak <none (AT) invalid (DOT) domain.fr>
wrote or quoted :

Per Newgro · Guest

Nomak wrote:

Nomak · Guest

On Sat, 10 Sep 2005 10:39:34 +0200

Per Newgro:

thx, the pdf http://www.jgoodies.com/articles/binding.pdf is quite interesting but i can't integrate a new library only for one Swing form.

Roedy Green:

way 1: directly modifies the other two : yes but it means writing again a new model which don't trigger, that's what i will do i think

way 2: custom event object: well since the methods which fires and receive the events are part of the JDK, it's a lot of rewritting similar to Sun work (licence problem)

Chris Smith:

yes some kind of master model.

Here is what i have got since the post:

public class MyBoundedRangeModel extends DefaultBoundedRangeModel {

public void setValueQuietly(int n) {
ChangeListener[] changeListeners = getChangeListeners();

for (int i = 0; i < changeListeners.length; i++) {
removeChangeListener(changeListeners[i]);
}

setValue(n);

for (int i = 0; i < changeListeners.length; i++) {
addChangeListener(changeListeners[i]);
}
}
}

This way, i don't propagate:
- i can't start back from BoundedRangeModel interface of else i will copy sun source
- value field is private in BoundedRangeModel, so no access is possible