How to automatically redirect from one page to another within a few seconds

The idea is to display a PageExpiredPage that is visible for a few seconds and automatically redirects to the HomePage, when the web session expires.

By the following code the PageExpiredPage displays with a bookmarkable link to the HomePage on it.

开发者_开发问答

PageExpiredPage.html:

Your session expired, log in anew by clicking
<a wicket:id="lnk-home-page" href="#"> here</a>
...

PageExpiredPage.java:

final Application app = Session.get().getApplication();
BookmarkablePageLink<? extends Page> lnkHomePage = new BookmarkablePageLink<? extends Page>("lnk-home-page", app.getHomePage());
add(lnkHomePage);
...

How to code in Wicket that the PageExpiredPage, when displayed, automatically redirects to HomePage after a configurable number of seconds?

---

A better solution than the RedirectPage is a custom behaviour. The obvious problem with RedirectPage is that you can't use a common base class for the layout of the page.

public class RedirectBehavior extends Behavior {

    private final Class<? extends Page> page;
    private final int redirectInSeconds;

    public RedirectBehavior(Class<? extends Page> page, int redirectInSeconds) {
        this.page = page;
        this.redirectInSeconds = redirectInSeconds;
    }

    @Override
    public void renderHead(Component component, IHeaderResponse response) {
        response.renderString(String.format("<meta http-equiv='refresh' content='%d;URL=%s' />", redirectInSeconds,
                RequestCycle.get().urlFor(page, null)));
    }
}

This way you can pass the return value from getHomePage() directly - no need for newInstance():

public class PageExpiredPage extends YourBasePage {
    public PageExpiredPage () {
        add(new RedirectBehavior(Application.get().getHomePage(), 5));
    }
}

---

I may have missed something, but it seems to me that RedirectPage can do just that:

Page that let the browser redirect. Use this if you want to direct the browser to some external URL, like Google etc. or if you want to redirect to a Wicket page, but with a delay. (my emphasis)

Constructor:

RedirectPage(Page page, int waitBeforeRedirectInSeconds)

RedirectPage extends org.apache.wicket.markup.html.WebPage and accepts a org.apache.wicket.Page as first argument.