How to add dynamic data (like current date) to PDF header or footer

<%
String template = getFormattedDate() + ", page ${page} ";
%>

<pd4ml:footer
pageNumberTemplate="<%=template%>"
titleAlignment="left"
pageNumberAlignment="right"
color="#008000"
initialPageNumber="1"
pagesToSkip="1"
fontSize="14"
areaHeight="18"/>