[jbossseam-issues] [JBoss JIRA] Commented: (JBSEAM-1299) s:link - Postback before redirect triggers Page Action of PREVIOUS page

Tue May 8 07:59:52 EDT 2007

    [ http://jira.jboss.com/jira/browse/JBSEAM-1299?page=comments#action_12361757 ] 

John Chesher commented on JBSEAM-1299:
--------------------------------------

Gavin,
Here is one example s:link in my appl. 

<s:link id="pickUser" value="#{usr.userName}&#160;&#160;" action="#{userSearch.selectUser}"/>

This appears on a User Search screen, where the link exists for each user returned by the search.  Clicking on the link will call the selectUser method, to "select" the user.  The outcome of that method will direct the user (via pages.xml) to an update page for the selected user.  That works fine, however, before redirecting to the User Update page, Seam is executing the method specified in the page action for the User Search screen, which I feel is inappropriate.  I usually use page actions to prepare data or similar activities before a page is rendered.  However, if the user is leaving that page and going to another, I don't want to execute the page action.

I gather from your comment that if I specify a viewID as the action, then the page action of the previous page will not be triggered, but if I specify a bean method, the page action of the previous page will be triggered.  Can you explain why you feel it is appropriate to trigger the page action, even when that page is not the page to which the user is being redirected?  Understanding the "why" may help me make design decisions ongoing.
Thanks!

> s:link  -  Postback before redirect triggers Page Action of PREVIOUS page
> -------------------------------------------------------------------------
>
>                 Key: JBSEAM-1299
>                 URL: http://jira.jboss.com/jira/browse/JBSEAM-1299
>             Project: JBoss Seam
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 1.2.0.GA
>         Environment: Seam 1.2-Patch1
>            Reporter: John Chesher
>
> Scenario:
> Page A contains an <s:link> to go to page B. Page A has a page action defined in pages.xml. When I click the s:link on Page A, to go to Page B, it invokes the page action for Page A before redirecting to Page B.  If I replace the s:link with an h:commandLink, it works as I would expect it to, i.e., no page action for Page A.
> I have now retested and I have this scenario in multiple instances within my application. In most cases, I didn't even realize that it was invoking the page action for Page A, as by luck the method was designed such that it did not throw an exception or cause any other noticeable problems. However, I finally noticed this behavior when my luck ran out and I wrote a page action method that threw an exception when called unitentionally in this situation.
> Is this perhaps a bug in s:link or am I not properly understanding and utilizing its capabilities?

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