losing the validation listener

Tom Eugelink tbee at tbee.org
Thu Sep 26 22:06:12 PDT 2013

I'm a bit ashamed to tell that I have not investigated this further yet. It feels like one of those issues that probably require a lot of spare time to figure out, and I decided to invest that time in more immediate issues around JFXtras. People are starting to use JFX in real life applications, and I wanted to make sure their problems are tackled first. My demo code needs to wait. This weekend I'll try to reproduce the problem again, should be easy to do.


On 2013-09-26 21:56, Richard Bair wrote:
> Hi Tom,
> Did this issue ever get resolved? It sounds very strange indeed, and we should have a JIRA filed for it if there is not one already.
> Thanks
> Richard
> On Apr 8, 2013, at 3:48 AM, Tom Eugelink <tbee at tbee.org> wrote:
>> Hi Werner,
>> It indeed is very similar (my code is public on Github, so no use adding it here), especially the selectedToggleProperty listener. I chose to reuse as much of the existing approach, being the getUserData().
>> What would be of interest to me is:
>> - the exact declaration of the enumValueProperty
>> - how you listen to changes on enumValueProperty
>> - and of course: what happens if you hide/disable the toggles with only one listener attached
>> Tom
>> On 2013-04-08 11:51, Werner Lehmann wrote:
>>> Hi Tom,
>>> I did something similar: toggle group for toggles which correspond to enum members. This one assume that the toggles correspond to the enum members in their declared order. It also uses an invalidation listener and disabling/enabling a toggle keeps the listener functional as I just tested with a test application.
>>> public class MintEnumToggleGroup<E extends Enum<E>> extends ToggleGroup
>>> {
>>>   public MintEnumToggleGroup(Class<E> enumClass)
>>>   {
>>>     this.enumClass = enumClass;
>>>     selectedToggleProperty().addListener(new InvalidationListener()
>>>     {
>>>       @Override
>>>       public void invalidated(Observable observable)
>>>       {
>>>         Toggle toggle = getSelectedToggle();
>>>         E value = null;
>>>         if (toggle != null)
>>>         {
>>>           int ordinal =
>>>             MintEnumToggleGroup.this.getToggles().indexOf(toggle);
>>>           value = MintEnumToggleGroup.this.enumClass
>>>             .getEnumConstants()[ordinal];
>>>         }
>>>         if (enumValue.get() != value)
>>>           enumValue.set(value);
>>>       }
>>>     });
>>>     ...
>>>   }
>>>   /**
>>>    * Bidirectionally bindable property representing the enum member
>>>    * of the selected toggle.
>>>    */
>>>   public ObjectProperty<E> enumValueProperty() { return enumValue; }
>>>   public E getEnumValue() { return enumValueProperty().get(); }
>>>   public void setEnumValue(E value) { enumValueProperty().set(value); }
>>> }
>>> Looks similar to what you are doing. Let me know if you want to look at the full source (toggle group and testcase).
>>> Rgds
>>> Werner
>>> On 07.04.2013 21:28, Tom Eugelink wrote:
>>>> Again some strange behavior I could use some pointers with. In JFXtras I've created an extended ToggleGroup which has a value property.
>>>> https://github.com/JFXtras/jfxtras-labs/blob/2.2/src/main/java/jfxtras/labs/scene/control/ToggleGroupValue.java
>>>> Basically what it does is listen to the selectedToggleProperty of ToggleGroup, and upon invalidation gets the user data associated with the now active toggle and puts that in the valueProperty. Simple, and now you can register and listen to the value of the toggle group. Which is exactly what I do in my basketball application by registering to the invalidated event.
>>>>       toggleGroup.valueProperty().addListener(new InvalidationListener() {...});
>>>> Now I have one very strange behavior; if I disable or hide the toggles, and then re-enable/show them again, the invalidation listener is no longer called. Some how it seems to have been removed from the listeners list. But the API documentation explicitly says it is a strong reference.
>>>> http://docs.oracle.com/javafx/2/api/javafx/beans/Observable.html#addListener(javafx.beans.InvalidationListener)
>>>> If I add a second dummy listener, then the first listener is not removed when disabled/hidden.
>>>> It very much reeks like a garbage collection thing. Any suggestions?
>>>> Tom

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