title: filterValue for a dataTable in Primefaces 5.3 always null
body: <p>I'm fairly new to using primefaces, and have a little doubt (already asked it on the primefaces forum but no reply so far)</p>
  
  <p>Is it possible to get the filter value on a xls dataExporter, more concretely on a postprocessor like method? <br><br>
  I can get the filtered value by declaring the filteredValue on the dataTable. But the filterValue variable isn't working as expected.</p>
  
  <p>I have both declared on my dataTable like this:</p>
  
  <p><code>filteredValue="#{parqueController.parqueListFiltered}" 
    filterValue="#{parqueController.parqueListFilter}"</code></p>
  
  <p>When I filter the values, the setter on the Bean class fires only for the filtered value, making the filter value always null.</p>
  
  <p>I ended finding this thread on PrimeFaces concerning this:</p>
  
  <p><a href="https://code.google.com/archive/p/primefaces/issues/5361" rel="nofollow noreferrer">https://code.google.com/archive/p/primefaces/issues/5361</a></p>
  
  <p>The issue was reported on version 3.5 and, as it looks, it was corrected/altered for later versions.. I'm using version 5.3</p>
  
  <p>Think this might be a bug? a regression? or am i just missing a point here and doing something wrong?</p>
  
  <p><a href="https://i.stack.imgur.com/qp5io.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qp5io.jpg" alt="enter image description here"></a></p>
  
  <p>Best regards and Thank you!</p>
  
  <p>Miguel Palmeiro</p>