Link to a page

Every link starts as an <a> tag with a wicket:id in the markup. Which component you attach to it depends on whether the click has to run code on the server.

HomePage.html

<a wicket:id="products">All products</a>

Link straight to a page with BookmarkablePageLink

When the link only navigates, use a BookmarkablePageLink. It renders the URL of the target page into the href, so the browser goes straight to that page, and the user can open it in a new tab or bookmark it.

HomePage.java

add(new BookmarkablePageLink<Void>("products", ProductListPage.class));

Pass PageParameters as the third argument to link to a page that needs them:

add(new BookmarkablePageLink<Void>("product", ProductPage.class,
    new PageParameters().add("id", product.getId())));

The target page needs a constructor without arguments or one that takes PageParameters; see Pass parameters to a page. A BookmarkablePageLink does not make its own page stateful, which matters on stateless pages.

Run code when the user clicks with Link

A Link is a click handler. Its href points back to the link itself; when the user clicks, Wicket calls onClick() on the server. After onClick(), Wicket renders the current page again unless you set another response page.

add(new Link<Void>("delete") {
    @Override
    public void onClick() {
        cart.remove(item);
        setResponsePage(CartPage.class);
    }
});

setResponsePage takes a page class or a page instance:

• setResponsePage(CartPage.class) and setResponsePage(CartPage.class, parameters) make Wicket create a new instance of the page, through a redirect to the URL of that page.
• setResponsePage(new ConfirmPage(order)) renders the instance you created. Use it when the next page needs objects or models that do not fit in a URL.

Why the response is a redirect, and when it is not, is explained in Redirects after a request.

Because its URL points at a component of the current page, a Link makes the page stateful. On a page that must stay stateless, use a StatelessLink or a BookmarkablePageLink.

Set the text of a link from a model

The markup between the <a> tags is the default text. To replace it from Java, give the link a body model. Here userModel is an IModel<User>:

add(new BookmarkablePageLink<Void>("profile", ProfilePage.class)
    .setBody(userModel.map(User::getDisplayName)));

The body is escaped like any model value.

Disable the link to the current page

In a menu, the entry for the page the user is on should not be a link. setAutoEnable(true) disables a link when it points to the page it is rendered on; for a BookmarkablePageLink that means a page of the same class.

add(new BookmarkablePageLink<Void>("menuProducts", ProductListPage.class)
    .setAutoEnable(true));

A disabled link on an <a> tag renders without its href, so the browser shows plain text. Use onConfigure with setEnabled(...) to disable a link for other reasons, as with any component; see Show, hide or disable a component.

Open the target in a popup window

setPopupSettings opens the target page in a new browser window with the size and features you choose:

add(new BookmarkablePageLink<Void>("help", HelpPage.class)
    .setPopupSettings(new PopupSettings("help").setWidth(600).setHeight(400)));

For links to other sites, use an ExternalLink. For links written in plain HTML, without Java code, see Turn plain links into page links with wicket:link.