JSF command links always perform a form submission via JavaScript, which breaks the web browser's "open in new window" or "open in new tab" feature. In plain JSF, you need to use an <h:outputLink> if you need this functionality. But there are two major limitations to <h:outputLink>.
Seam provides the notion of a
page action
to help solve the first problem, but this does nothing to help us with the second problem. We
could
work around this by using the RESTful approach of passing a request parameter and requerying for the selected object on the server side. In some cases—such as the Seam blog example application—this is indeed the best approach. The RESTful style supports bookmarking, since it does not require server-side state. In other cases, where we don't care about bookmarks, the use of @DataModel and @DataModelSelection is just so convenient and transparent!
To fill in this missing functionality, and to make conversation propagation even simpler to manage, Seam provides the <s:link> JSF tag.
The link may specify just the JSF view id:
<s:link view=“/login.xhtml” value=“Login”/>
Or, it may specify an action method (in which case the action outcome determines the page that results):
<s:link action=“#{login.logout}” value=“Logout”/>
If you specify
both
a JSF view id and an action method, the 'view' will be used
unless
the action method returns a non-null outcome:
<s:link view="/loggedOut.xhtml" action=“#{login.logout}” value=“Logout”/>
The link automatically propagates the selected row of a DataModel using inside <h:dataTable>:
<s:link view=“/hotel.xhtml” action=“#{hotelSearch.selectHotel}” value=“#{hotel.name}”/>
You can leave the scope of an existing conversation:
<s:link view=“/main.xhtml” propagation=“none”/>
You can begin, end, or nest conversations:
<s:link action=“#{issueEditor.viewComment}” propagation=“nest”/>
If the link begins a conversation, you can even specify a pageflow to be used:
<s:link action=“#{documentEditor.getDocument}” propagation=“begin”
pageflow=“EditDocument”/>
The taskInstance attribute if for use in jBPM task lists:
<s:link action=“#{documentApproval.approveOrReject}” taskInstance=“#{task}”/>
(See the DVD Store demo application for examples of this.)
Finally, if you need the "link" to be rendered as a button, use <s:button>:
<s:button action=“#{login.logout}” value=“Logout”/>
