Handle file download request in JSF 2.1 + PrimeFaces 5.1 - jsf

Question

I have a web application in JSF 2.1 + PrimeFaces 5.1 that has a datatable where I list records from a database. Each row can be expanded to show some details, and there I have a button to download a XML file that has its contents saved in the DB.
<p:dataTable id="event_queue_table_id" var="event" value="#{eventQueueBean.eventQueue}" rowKey="#{event.id}">
...
<p:rowExpansion>
...
<p:commandButton ajax="false" icon="ui-icon-arrowthick-1-s" actionListener="#{eventQueueBean.downloadXml(event.id)}">
<p:fileDownload value="#{fileBean.file}"/>
</p:commandButton>
</p:rowExpansion>
</p:dataTable>
I want to fetch the XML contents from the DB, create the file and prompt the user to open/save it. The bean that controls this datatable looks like this:
#ManagedBean
#ViewScoped
public class EventQueueBean implements Serializable {
#ManagedProperty(value="#{fileBean}")
private FileBean fileBean;
public void downloadXml(BigDecimal eventId) {
try {
logger.entry(eventId);
DtoGetXmlEvent dtoGetXmlEvent = null;
if (eventId != null) {
dtoGetXmlEvent = eventQueueService.getXmlEvent(eventId);
String xml = dtoGetXmlEvent.getXml();
if (xml == null) {
// show error message stating that file does not exist
} else {
this.fileBean.download(xml, eventId + ".xml", "application/xml");
}
}
logger.exit();
} catch (...)
}
}
}
And my FileBean is:
#ManagedBean
#ViewScoped
public class FileBean implements Serializable {
private static final long serialVersionUID = 1L;
private static final Logger logger = LogManager.getLogger(FileBean.class);
private StreamedContent file;
public FileBean() {
logger.entry();
}
public void download(String content, String fileName, String contentType) {
logger.entry(fileName, contentType);
InputStream stream = new ByteArrayInputStream(content.getBytes(StandardCharsets.UTF_8));
file = new DefaultStreamedContent(stream, contentType, fileName);
logger.exit();
}
public StreamedContent getFile() {
return file;
}
public void setFile(StreamedContent file) {
this.file = file;
}
When I try to download an empty XML (the DB retrieves NULL content), the open/save file prompt does not show, but if I try to refresh the page I get the "To display this page, Firefox must send information that will repeat any action (such as a search or order confirmation) that was performed earlier.". How can I avoid this?