Start interval after button click wicket - wicket

Question

I'm trying to start an interval after button click.
button = form.add(new AjaxButton("button") {
#Override
protected void onSubmit(AjaxRequestTarget target, Form<?> form) {
AjaxSelfUpdatingTimerBehavior ajaxSelfUpdatingTimerBehavior = new AjaxSelfUpdatingTimerBehavior(Duration.seconds(5)) {
private static final long serialVersionUID = 1L;
#Override
protected void onPostProcessTarget(AjaxRequestTarget target) {
logger.debug("onPostProcessTarget");
}
};
this.add(ajaxSelfUpdatingTimerBehavior);
}
});
});
The previous AjaxSelfUpdatingTimerBehavior does not start after button click. How can I make it start?
The wierd thing is if I add a new one like this after the previous block
button.add(new AjaxSelfUpdatingTimerBehavior(Duration.seconds(5)) {
private static final long serialVersionUID = 1L;
#Override
protected void onPostProcessTarget(AjaxRequestTarget target) {
logger.debug("onPostProcessTarget2");
}
});
both of them start. But the last one also updates the dom which I don't want.
So all in all how can I start an interval after button click? (similarly to first code snippet)

Answer 1

Unlike regular form submission, ajax form submission (via an ajax button like you do here) is not going to re-render anything that you don't explicitly state you want re-rendered by performing target.add(...) on it.
What this means is that any changes you make to the component hierarchy or components themselves (like adding a new behavior) are going to stay in the back-end until you either update the individual components, or re-render the whole page.
In order to propogate any state changes in an ajax request call target.add(this) in your form submission. This will make wicket update the component and hence add the new behaviors of it to the front-end.
So given your example the code should look like the following:
button = form.add(new AjaxButton("button") {
#Override
protected void onSubmit(AjaxRequestTarget target, Form<?> form) {
AjaxSelfUpdatingTimerBehavior ajaxSelfUpdatingTimerBehavior = new AjaxSelfUpdatingTimerBehavior(Duration.seconds(5)) {
private static final long serialVersionUID = 1L;
#Override
protected void onPostProcessTarget(AjaxRequestTarget target) {
logger.debug("onPostProcessTarget");
}
};
this.add(ajaxSelfUpdatingTimerBehavior);
target.add(this);
}
});
});