Wicket DropDownChoice onSelectionChanged method removed after version update

Question

I was designated as a developer to upgrade our old wicket app from 6.x to 8.x. I am resolving multiple errors one by one, but (since I never worked with wicket) one I am unable to move on with.

In version 6.x it had DropDownChoice with overriden onSelectionChanged which no longer exists in version 8.x and I am unable to find any info about deprecation (going through 7.x versions...) so it seems they just removed it .. what are my alternatives here? The aforementioned code:

booleanType = new DropDownChoice<BooleanType>("booleanType", new PropertyModel<>(this, "selectedBooleanType"), booleanTypes) {
            

            @Override
            protected void onSelectionChanged(BooleanType newSelection) {
                super.onSelectionChanged(newSelection);
                selectedBooleanType = newSelection;
            }
        };

EDIT: Similar question that I found only later Wicket 6 to 8 upgrade: RadioGroup.onSelectionChanged() replacement

for those wondering how to update the value since it is not coming as an argument of the method anymore:

                selectedType = (YourChoiceType) super.getFormComponent().getDefaultModelObject();

Answer 1

wantOnSelectionChangedNotifications moved to FormComponentUpdatingBehavior. From the changelog:

// Wicket 7.x
new CheckBox("id", model) {
    protected boolean wantOnSelectionChangedNotifications() {
        return true;
        }
 
    protected void onSelectionChanged(Boolean newSelection) {
        // do something, page will be rerendered;
    }
};
 
 
// Wicket 8.x
new CheckBox("id", model)
.add(new FormComponentUpdatingBehavior() {
    protected void onUpdate() {
        // do something, page will be rerendered;
    }
 
    protected void onError(RuntimeException ex) {
        super.onError(ex);
    }
});

(The example uses a CheckBox but it also applies to DropDownChoice).

For another example see the wiki.