Building a Wicket Component Which Updates Itself When the Model Changes

For a component to update itself when model is updated:

• Implement a method (e.g. update) that updates the UI components. This can be called from:
  • the constructor and
  • whenever the model is changed.
• Override the onModelChanged method, like this:

@Override
protected void onModelChanged() {

super.onModelChanged();
update();

}

• onModelChanged will be automatically called by Wicket IF the reference of the Model Object has changed. Deep changes (e.g. changes in one of its fields) will not be detected.
• So in order for onModelChanged be called, either:
  • replace the Model Object with a modified clone (in which case Wicket will automatically call it) OR
  • call onModelChanging & onModelChanged manually.
• Ensure that the Component is added to an AjaxRequestTarget and it will be updated via AJAX automatically