Primefaces p:fileDownload inside p:treeTable doesn't work? - jsf-2

Question

I have such structure:
<p:treeTable value="#{cmpDocumentTree.root}" var="v" id="#{tableId}" selectionMode="single"
selection="#{cmpDocumentTree.selectedNode}">
<p:ajax event="expand" listener="#{cmpDocumentTree.onNodeExpand}" />
<p:ajax event="collapse" listener="#{cmpDocumentTree.onNodeCollapse}" />
<p:ajax event="select" listener="#{crudBean.edit(cmpDocumentTree.selectedNode.data)}"
update=":#{formDialogUpdate}" oncomplete="#{formDialog}.show()" />
<p:column headerText="Nazwa" sortBy="#{v.name}" style="min-width: 200px;">
<h:outputText value="#{v.name}" />
</p:column>
<p:column headerText="Pliki" width="300">
<ui:repeat var="_file1" value="#{v.files}">
<h:commandLink value="#{_file1.originalFilename}">
<p:fileDownload
value="#{fileDownloadController.getFile(_file1.originalFilename, _file1.storedFilename, _file1.contentType)}" />
</h:commandLink>
<br />
</ui:repeat>
</p:column>
</p:treeTable>
But - p:fileDownload doesn't work. The fileDownloadController.getFile(...) method is not fired at all.
When I put the same method inside p:dataTable, then it works perfectly.
EDIT:
v.files comes from ComDocument entity - it is relation one-to-many document-to-files.
#Entity
#Table(name = "com_documents", schema = "public")
#SequenceGenerator(name = "COM_DOCUMENTS_SEQ", sequenceName = "COM_DOCUMENTS_SEQ", allocationSize = 1)
public class ComDocument implements EntityInt, java.io.Serializable {
(...)
#OneToMany(fetch = FetchType.EAGER, mappedBy = "document", cascade = CascadeType.ALL, orphanRemoval = true)
private List<ComDocumentFile> files;
public void setFiles(List<ComDocumentFile> files) {
this.files = files;
}
public List<ComDocumentFile> getFiles() {
return files;
}
Could you help me? Thanks.

Answer 1

I've never had any luck with the FileDownload working inside an ajax request. I have not bothered to dig into the source as it is never a show stopper (and it really doesn't make sense to use it as an ajax request--you're getting a complete file, not updating a page).
The simple solution here is to make sure that your command button has "ajax=false"
<p:commandLink value="#{_file1.originalFilename}" ajax="false">
<p:fileDownload
value="#{fileDownloadController.getFile(_file1.originalFilename, file1.storedFilename, _file1.contentType)}" />
</p:commandLink>
http://www.primefaces.org/showcase/ui/fileDownload.jsf
You'll notice all the examples have the ajax functionality disabled. If you're using h:commandButton for style I suggest using p:commandLink and styling it to be a button.
Best of luck, I'm pretty sure this will fix it. Also--make sure your "download objects" are final. You need to make sure that the data-source is referring to the same reference and not creating a new instance on each request.