Groovy xml parse then rebuild

Question

With more than a little help from daviderossi.blogspot.com I have managed to get some code working to replace an xml value with another

def fm_xml = '''<?xml version="1.0" encoding="UTF-8"?>
<MAlong>
<Enquiry.ID>SC11147</Enquiry.ID>
<student.name_middle></student.name_middle>
<student.name_known></student.name_known>
<student.name_previous></student.name_previous>
<student.name_cert>John REnfrew</student.name_cert>
<student.detail_gender>M</student.detail_gender>
<student.sign_name>John Renfrew</student.sign_name>
<student.sign_date>05/01/2010</student.sign_date>
</MAlong>'''

xml = new XmlParser().parseText(fm_xml)
ix = xml.children().findIndexOf{it.name() =='student.name_middle'}
nn = new Node(xml, 'student.name_middle', "NEW")
if (ix != -1 ) {
xml.children()[ix] = nn
nn.parent = xml
}
writer = new StringWriter()
new XmlNodePrinter(new PrintWriter(writer)).print(xml)
result = writer.toString()

This give me the following output BUT I would love it to be with properly formed closing tags otherwise XPath queries on the new data will then fail..

so for example

<student.name_known/>

needs to become

<student.name_known></student.name_known>

Any ideas??

<MAlong>
<Enquiry.ID>
 SC11147
</Enquiry.ID>
<student.name_middle>
 NEW
</student.name_middle>
<student.name_known/>
<student.name_previous/>
<student.name_cert>
 John REnfrew
</student.name_cert>
<student.detail_gender>
 M
</student.detail_gender>
<student.sign_name>
 John Renfrew
</student.sign_name>
<student.sign_date>
 05/01/2010
</student.sign_date>
<student.name_middle>
 NEW
</student.name_middle>
</MAlong>

Answer 1

<student.name_known/>

Is perfectly well formed, and XPath queries should function perfectly well on this XML structure.