How to convert a pojo to xml using "as" keyword - grails

Question

I have a requirement to send an object as xml to a webservice. I already have the pojo, now I need to convert it to xml using Groovy. In grails I have used the as keyword, what is the equivalent code to do this in Groovy?
Example Grails code:
import grails.converters.*
render Airport.findByIata(params.iata) as XML

Answer 1

A naive example of doing this with StreamingMarkupBuilder would be:
class Airport {
String name
String code
int id
}
Writable pogoToXml( object ) {
new groovy.xml.StreamingMarkupBuilder().bind {
"${object.getClass().name}" {
object.getClass().declaredFields.grep { !it.synthetic }.name.each { n ->
"$n"( object."$n" )
}
}
}
}
println pogoToXml( new Airport( name:'Manchester', code:'MAN', id:1 ) )
Which should print:
<Airport><name>Manchester</name><code>MAN</code><id>1</id></Airport>

Answer 2

The as keyword is actually part of the Groovy language spec. The part you are missing is the XML class that does the conversion. This is really just a fancy class that walks the POJO and writes the XML (possibly using MarkupBuilder).
Groovy does not have a built-in class like grails.converters.XML that makes it so easy. Instead, you'll need to manually build the XML using MarkupBuilder or StreamingMarkupBuilder.
Neither of these will automatically convert a POJO or POGO to XML, you'll have to either process this yourself manually, or use reflection to automate the process.
I'd suggest that you might be able to copy the grails converter over, but it may have a lot of dependencies. Still, it's open source, that might be a starting point if you need a more reusable component.