Ajax components

Every component on this page renders an Ajax behavior and calls a method with an AjaxRequestTarget, or an Optional<AjaxRequestTarget> for the fallback components, which is empty when the request came in without Ajax. Components from wicket-core need no extra dependency; the others are in the wicket-extensions module. To add Ajax to a component that has none, use an Ajax behavior.

Links and buttons

AjaxLink, AjaxFallbackLink, AjaxButton and AjaxSubmitLink are in org.apache.wicket.ajax.markup.html and its form subpackage; the indicating variants in org.apache.wicket.extensions.ajax.markup.html.

add(new AjaxButton("save") {
    @Override
    protected void onSubmit(AjaxRequestTarget target) {
        repository.save(form.getModelObject());
        target.add(feedback);
    }

    @Override
    protected void onError(AjaxRequestTarget target) {
        target.add(feedback);
    }
});

Form fields

AutoCompleteTextField takes an AutoCompleteSettings in its constructor for the throttle delay, the minimum input length and the look of the list. Suggestions are rendered with an IAutoCompleteRenderer; the default calls toString().

AutoCompleteSettings settings = new AutoCompleteSettings()
    .setThrottleDelay(400)
    .setMinInputLength(2);

add(new AutoCompleteTextField<String>("city", cityModel, settings) {
    @Override
    protected Iterator<String> getChoices(String input) {
        return cities.findByPrefix(input, 10).iterator();
    }
});

Tables and paging

AjaxPagingNavigator adds the nearest parent of the repeater that outputs a markup id to the target, and the whole page when there is none, so give the container around the repeater a markup id. AjaxFallbackDefaultDataTable sets its own. See Page through data.

Panels, dialogs and tabs

ModalDialog brings no styling of its own. Add a DefaultTheme behavior, or style its CSS classes yourself. closeOnEscape(), closeOnClick() and trapFocus() switch on the matching behavior.

HomePage.html

<a wicket:id="open">Open the dialog</a>
<div wicket:id="dialog"></div>

HomePage.java

ModalDialog dialog = new ModalDialog("dialog");
dialog.add(new DefaultTheme());
dialog.closeOnEscape();
dialog.setContent(new Label(ModalDialog.CONTENT_ID, "Saved."));
add(dialog);

add(new AjaxLink<Void>("open") {
    @Override
    public void onClick(AjaxRequestTarget target) {
        dialog.open(target);
    }
});

Trees

The tree components are in org.apache.wicket.extensions.markup.html.repeater.tree. Expanding and collapsing a node updates the tree with Ajax.

HumanTheme and WindowsTheme are behaviors that give a tree a look. The repeaters these trees build on are described in Repeaters.