groovyとsaxonでworldbank.orgから日本のCO2排出量をXQueryで取得する

groovyとsaxonでworldbank.orgから日本のCO2排出量をXQueryで取得するには、以下のコードを実行します。

@Grab(group='net.sf.saxon', module='saxon', version='8.7')
import net.sf.saxon.*
import net.sf.saxon.query.*
import org.xml.sax.*
import javax.xml.transform.sax.*
import javax.xml.transform.stream.*

// source url:CO2排出量(kt)
yearFrom = "2002"
yearTo = "2007"
countries = "jpn"
base = "http://api.worldbank.org/countries/${countries}/indicators/EN.ATM.CO2E.KT"
param = "?per_page=1000&date=${yearFrom}:${yearTo}"
sourceurl = "${base}${param}"

// XQuery
String query =
'''
declare namespace wb = "http://www.worldbank.org";
for $elem in //wb:data/wb:data
order by $elem/wb:date/text()
return 
<result> 
  <name>{$elem/wb:date/text()}</name>
  <value>{$elem/wb:value/text()}</value>
</result>
'''
println query

// XQueryを実行
conf = new Configuration()
sqc = new StaticQueryContext(conf)
dqc = new DynamicQueryContext(conf)
xq = sqc.compileQuery(query)
sqc =xq.getStaticContext()
di = sqc.buildDocument(new SAXSource(new InputSource(new URL(sourceurl).newInputStream())))
dqc.setContextNode(di)
xq.run(dqc, new StreamResult(System.out), new Properties())

動作環境
groovy1.8.2, JDK6 Update27, saxon 8.7