Parse XML using Groovy: Override charset in declaration and add XML processing instruction - groovy

Question

My initial question have been answered, but that did just open up for further issues.
Example code
Using Groovy 2.0.5 JVM 1.6.0_31
import groovy.xml.*
import groovy.xml.dom.DOMCategory
def xml = '''<?xml version="1.0" encoding="UTF-16"?>
| <?xml-stylesheet type="text/xsl" href="Bp8DefaultView.xsl"?>
|<root>
| <Settings>
| <Setting name="CASEID_SEQUENCE_SIZE">
| <HandlerURL>
| <![CDATA[ admin/MainWindow.jsp ]]>
| </HandlerURL>
| </Setting>
| <Setting name="SOMETHING_ELSE">
| <HandlerURL>
| <![CDATA[ admin/MainWindow.jsp ]]>
| </HandlerURL>
| </Setting>
| </Settings>
|</root>'''.stripMargin()
def document = DOMBuilder.parse( new StringReader( xml ) )
def root = document.documentElement
// Edit: Added the line below
def pi = document.createProcessingInstruction('xml-stylesheet', 'type="text/xsl" href="Bp8DefaultView.xsl"');
// Edit #2: Added line below
document.insertBefore(pi, root)
use(DOMCategory) {
root.Settings.Setting.each {
if( it.'#name' == 'CASEID_SEQUENCE_SIZE' ) {
it[ '#value' ] = 100
}
}
}
def outputfile = new File( 'c:/temp/output.xml' )
XmlUtil.serialize( root , new PrintWriter(outputfile))
// Edit #2: Changed from root to document.documentElement to see if that
// would make any difference
println XmlUtil.serialize(document.documentElement)
Problem description
I'm trying to parse a XML-file exported from a third party tool, and before promoting it to stage and production I need to replace certain attribute values. That is all ok, but in addition I must keep the encoding and ref. to the stylesheet.
Since this is pretty static it is totally ok to have both the encoding and the stylesheet ref. definition in a property-file, meaning: I do not need first to find the declarations in the original file.
Encoding in declaration issue
As shown in this answer found here on StackOverFlow you can do
new File('c:/data/myutf8.xml').write(f,'utf-8')
I have also tried
XmlUtil.serialize( root , new GroovyPrintStream('c:/temp/output.txt', 'utf-16'))
but it did not solve the problem for me either. So I have not understood how to override the UTF-value.
Processing instruction issue
Simply, how do I add
<?xml-stylesheet type="text/xsl" href="Bp8DefaultView.xsl"?>
to the output?
Update - This can be done like this
def pi = document.createProcessingInstruction('xml-stylesheet', 'type="text/xsl" href="Bp8DefaultView.xsl"');
The processing instruction is being added like this, this guideline showed me, but still I do not get the output.
document.insertBefore(pi, root) // Fails

Answer 1

All issues in this question has been answered in another question I raised, see Groovy and XML: Not able to insert processing instruction
The trick is that I expected
document.documentElement
to contain the processing instruction. But that is wrong, documentElement is:
...This is a convenience attribute that allows direct access to the child node that is the document element of the document...
Where the processing instruction is just another child node. So what I instead had to use was either the LSSerializer or the Transfomer. See Serialize XML processing instruction before root element for details.