8.5. Using and

JSF command links always perform a form submission with JavaScript, which causes problems with the web browser's "open in new window" or "open in new tab" feature. If you require this functionality in plain JSF, you need to use an <h:outputLink>, but there are two major limitations to this method:
  • JSF provides no way to attach an action listener to an <h:outputLink>, and
  • JSF does not propagate the selected row of a DataModel, since there is no actual form submission.
To solve the first problem, Seam implements the notion of a page action, but this does not solve the second. It is possible to work around this by passing a request parameter and requerying for the selected object on the server-side, and in some cases (like the Seam blog example application), this is the best approach. Since it is RESTful and does not require server-side state, bookmarking is supported. In other cases, where bookmarking is unnecessary, @DataModel and @DataModelSelection are transparent and convenient.
To replace this missing functionality, and to simplify conversation propagation further, Seam provides the <s:link> JSF tag.
The link can specify only the JSF ID: 
<s:link view="/login.xhtml" value="Login"/>
It can also specify an action method, in which case the action outcome determines the page that results: 
<s:link action="#{login.logout}" value="Logout"/>
If both a JSF view ID and an action method are specified, 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 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 specify the use of a particular pageflow: 
<s:link action="#{documentEditor.getDocument}" propagation="begin" 
   pageflow="EditDocument"/>
The taskInstance attribute is for use in jBPM task lists, as follows. See Section 1.8, “A complete application featuring Seam and jBPM: the DVD Store example” for an example. 
<s:link action="#{documentApproval.approveOrReject}" 
   taskInstance="#{task}"/>
Finally, use <s:button> if you want the "link" rendered as a button: 
<s:button action="#{login.logout}" value="Logout"/>