⁠9.3. Starting conversations with GET requests

JSF does not define action listeners triggered when a page is accessed through a non-Faces request (for example, an HTTP GET request). This can occur when a user bookmarks the page, or navigates to the page through <h:outputLink>.
Sometimes you want a conversation to begin immediately when a page is accessed. As there is no JSF action method, you cannot annotate the action with @Begin.
Further problems arise when the page requires state to be fetched into a context variable. You have seen two methods of solving this problem. If the state is held in a Seam component, you can fetch the state in a @Create method. If not, you can define a @Factory method for the context variable.
If neither option works for you, Seam allows you to define a page action in the pages.xml file. 
​<pages> 
​  <page view-id="/messageList.xhtml" action="#{messageManager.list}"/>
​  ... 
​</pages>
This action method is called at the beginning of the render response phase — that is, any time the page is about to be rendered. If a page action returns a non-null outcome, Seam processes appropriate JSF and Seam navigation rules. This can result in a completely different page rendering.
If beginning a conversation is all you want to do before rendering the page, you can use a built-in action method: 
​<pages> 
​  <page view-id="/messageList.xhtml" action="#{conversation.begin}"/>
​  ... 
​</pages>
You can also call this built-in action from a JSF control, and #{conversation.end} similarly ends conversations.
You can use the <begin-conversation> element for further control over joining existing conversations, or beginning a nested conversation or an atomic conversation; as follows: 
​<pages> 
​  <page view-id="/messageList.xhtml"> 
​    <begin-conversation nested="true" /> 
​  <page> 
​  ... 
​</pages>
There is also a <end-conversation> element. 
​<pages> 
​  <page view-id="/home.xhtml"> 
​    <end-conversation/> 
​  <page> 
​  ...
​</pages>
You have five options to begin a conversation immediately when a page is accessed:
  • Annotate the @Create method with @Begin
  • Annotate the @Factory method with @Begin
  • Annotate the Seam page action method with @Begin
  • Use <begin-conversation> in pages.xml
  • Use #{conversation.begin} as the Seam page action method