A shot at answering your questions... This assumes you're using Wicket 1.4.x.
First, you can have many levels of Page classes, often mimicking the overlap of the design and function. For example, say you have an application where people "Write", "Browse" and "Read" user-created books.
RootPage - common headers/footers, javascript imports
AbstractWritePage extends RootPage - for anything regarding authoring
AbstractBrowsePage extends RootPage - browsing
AbstractReadPage extends ReadPage - reading
Then, I implement something like:
FullLibraryPage extends AbstractBrowsePage
FilterSearchPage extends AbstractBrowsePage
In the long run, it gets complicated, but very powerful.
Secondly, your Panel components that go visible/invisible. If you're using Wicket 1.4.x, you should look at the overrideable method onConfigure() for each Panel. In this panel, you can set the visibility like:
@Override
protected void onConfigure() {
super.onConfigure();
setVisible(!navTriggered);
}
where navTriggered is a boolean value residing in the containing page. Then, your link could do a simple:
@Override
protected void onClick(AjaxRequestTarget target) {
navTriggered = false;
target.addComponent(/* Appropriate panels; see below for multiples */);
}
The advantage to this is that you can have multiple panels triggered by the same boolean variable. There is nothing wrong with creating all of your panels at page creation time, even if they start out invisible.
Finally, if you have a lot of panels that need to be changed/triggered/etc, consider pairing an IVisitor with a marking interface. Something like...
public class Panel1 implements MyPanelGroup { ... }
public class Panel2 implements MyPanelGroup { ... }
Then, you can use an IVisitor to visit every instance of MyPanelGroup in a page and do something with visibility (either set visibility, add it to the AjaxRequestTarget, etc).
Hope that answers something :)