jsf - How to use a default generated ID in a Facelet tag -

i've created custom facelet tag. id fall default j_idtxxx if have left out entire id attribute when not set in xhtml.

so, <my:tag id="fiets"/> rendered <span id="fiets"/>.

but, <my:tag/> should rendered <span id="j_idtxxx"/>.

if use <h:anytag id="#{id}"/> in tag file, fails on empty id attribute. there way rendered default generated id? create like:

<c:set var="id" value="#{empty id ? use_default : id}" /> 

but don't know use @ use_default.

the functionality available uiviewroot#createuniqueid(). current uiviewroot instance in el available implicit object #{view}.

so, should do:

<c:set var="id" value="#{empty id ? view.createuniqueid() : id}" />