I have a file that stores blob fields.
So I used commandlink and ActionListener to create a file and store it in the appropriate format which is here a pdf.
But how can I directly open it from the commandLink?

This is what I've done so far.
The printInvoive method creates the file on the disk and also gets the link.

<t:column headerstyleClass="#{style.dataTable_column_headerstyleClass}">
<f:facet name="header">
<h:outputText value="#{msg.invoice_no}" />
</f:facet>
<a4j:commandLink actionListener="#{invoice.printInvoice}" >
<h:outputText value=" #{data.invoiceNo}" />
<f:param id="invoiceDealerCodePrintId" name="invoiceDealerCodePrint" value="#{data.invoiceDealerCode}" />
<f:param id="invoiceNoPrintId" name="invoiceNoPrint" value="#{data.invoiceNo}" />
</a4j:commandLink>
<rich:spacer />
</t:column>