xmlslurper node remove issues - groovy

Question

i have a xml from where i wish to remove few nodes. The idea i used is to run through all the root node children and keep writing to another file those nodes which i dont need to delete.
One problem I see is: the node attributes gets reordered in the written file which i dont want
my code looks like:
def xml = new XmlSlurper(false, false).parse(args[0])
ant.delete(file:fileName)
File f = new File(fileName)
xml.children().each{
String str = it.#name
if(some condiotion == false)
f << groovy.xml.XmlUtil.serialize(it)
}
another problem is that in the begining of every node it inserts
<?xml version="1.0" encoding="UTF-8"?>

Answer 1

There is no concrete example of the xml present in the question. Here is an example how a Node can be removed:
import groovy.xml.XmlUtil
def xml = '''
<School>
<Classes>
<Class>
<Teachers>
<Name>Rama</Name>
<Name>Indhu</Name>
</Teachers>
<Name>Anil</Name>
<RollNumber>16</RollNumber>
</Class>
<Class>
<Teachers>
<Name>Nisha</Name>
<Name>Ram</Name>
</Teachers>
<Name>manu</Name>
<RollNumber>21</RollNumber>
</Class>
</Classes>
</School>
'''
def parsed = new XmlSlurper().parseText( xml )
parsed.'**'.each {
if(it.name() == 'Teachers') {
it.replaceNode { }
}
}
XmlUtil.serialize( parsed )
In the above example, Teachers node is removed by doing a depthFirst search and iterating over each node and finally using replaceNode with an empty Closure. I hope this can be used as the logic you want.
PS: I have omitted the File operations for brevity.

Answer 2

The API work with a replacementStack. So, the replaceNode {} will show the result only when you serialize the node like:
GPathResult body = parsePath.Body
int oldSize = parsePath.children().size()
body.list()
body[0].replaceNode {} // Remove o no, mas não será visivel para o objeto pai, somente no momento de serializacao. Pois a API adiciona em uma pilha de alteracao que será usada na serializacao
String newXmlContent = XmlUtil.serialize(parsePath)
GPathResult newParsePath = new XmlSlurper().parseText(newXmlContent)
int newSize = newParsePath.children().size()
assertNotNull(this.parsePath)
assertEquals(2, oldSize)
assertEquals(1, newSize)
assertTrue(newSize < oldSize)
assertNotNull(body)