Multiple <f:viewAction> in <f:metadata>

Question

I am developing a CMS using JSF 2.3. I need to pass a GET parameter to every page indicating the site that the user is managing. To do this I am using <f:viewParam> in all pages, but I have the following doubts:

1. Is it OK to use multiple <f:viewAction> for multiple managed beans like the following example?

<f:metadata>
    <f:viewParam name="form" value="#{editFormWebBean.formIdParam}"/>
    <f:viewParam name="site" value="#{headerWebBean.siteIdParam}"/>
    <f:viewAction action="#{editFormWebBean.init}" />
    <f:viewAction action="#{headerWebBean.init}" />
</f:metadata>

This works, but I am not sure if it is OK.

2. Is there a way to avoid replicating in every page the <f:viewParam> for the site parameter? I tried with includeViewParams, but doesn't worked if I don't include the <f:viewParam> in the source and destination page (from page1.xhtml to page2.xhtml)

3) Can I define multiple <f:metadata> tags? For example if I am using templates and multiple ManagedBeans pare page (one for the header, one for the menu and so on).

Thank you and sorry about my english.

Answer 1

1. it's okay to have as many <f:viewParam> and <f:viewAction> as long as they work well together, but please make sure these are meant to initialize the view "JSF page" not the backing beans, use @PostConstruct on the baking beans to initialize them, also but in your mind that <f:viewAction> is only executed on GET request by default any subsequent POST (postback) requests don't invoke the action unless it has onPostBack="true" attribute. more on these tags can be found in this great answer [What can <f:metadata> , <f:viewParam> and <f:viewAction> be used for?][1]

2. put it in a template using the templating feature of JSF like this:

template.xhtml

<f:metadata>
   <f:viewParam name="site" value="#{headerWebBean.siteIdParam}"/>
   <ui:insert name="metadata"/>
</f:metadata>

page.xhtml

<ui:composition template="template.xhtml">
    <ui:define name="metadata">
        <!-- whatever metadata you want to add-->
    </ui:define>
 </ui:comosition>

3. no it's one metadata tag per page, use it like the example above. [1]: https://stackoverflow.com/a/6377957/4649524