TableView. Observing changes: observing of non-property data
<p>I use JavaFX to create interface for my program. So I have <code>TableView</code> that represent list of such objects</p>

<pre><code>public class CQuestAnswer
{   
    private SimpleStringProperty sCaption;
    private CQuestStage stgNext;
}
</code></pre>

<p><code>stgNext</code> is a pointer to existing object or <code>null</code> if there is on acceptable one.</p>

<p>I need to observe changes of list items, so I set listeners when I create <code>ObservableList</code></p>

<pre><code>    ObservableList&lt;CQuestAnswer&gt; olData = FXCollections.observableList(lstANswers, (CQuestAnswer param) -&gt; {

        param.paramSCaption().addListener((ObservableValue&lt;? extends String&gt; observable, String oldValue, String newValue) -&gt; {
            setQuestionnaireChanged(true);
        });

        return new Observable[]{param.paramSCaption()
                                };
    });
</code></pre>

<p>To observe <code>stgNext</code> I need to do the same. But as far as <code>stgNext</code> is not <code>Property</code> and I need to observe changes of itself not its members value. I mean that when user changes next step <code>stgNext</code> pointer changes its value, not object that it points.</p>

<p>How can I do this?</p>