Saturday, November 12, 2011

Primefaces global AJAX events

You can use jQuery global AJAX events with PrimeFaces to refactor behaviors that appear on multiple components.  A good example is if you have a data grid with multiple p:commandLinks and other controls that execute different methods and re-render the grid, and need to run the same onComplete in all of them.

For example, if you start with something like this:

<h:panelGroup id="grid">...</h:panelGroup>
<p:commandLink update="grid" actionListener="#{bean.update1}" onComplete="updateGrid()"/>
<p:commandLink update="grid" actionListener="#{bean.update2}" onComplete="updateGrid()"/>
<p:commandLink update="grid" actionListener="#{bean.update3}" onComplete="updateGrid()"/>

You could pull the updateGrid() statement out into an AJAX listener like this


jQuery(document).ajaxComplete(function(e, xhr, opts) {
  $response = jQuery(xhr.responseXML);
  if ($response.find("div[id$='grid']").length > 0) {
     updateGrid();
  }
});
By using ajaxComplete and parsing the XHR response object, you can see which DIV was going to be impacted by the partial update.  That way, if you had some other AJAX controls (say, an autocompleter) that you didn't want to trigger the updateGrid() function, you could filter that out.  Another option would be to set global=false on the specific Primefaces components that you don't want to fire the global jQuery ajaxComplete event.  The Primefaces autocompleter doesn't support this in Primefaces 2.x but does in 3.0.  
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