Wrapping the result of an XQuery query into an XML document is very useful if you're working with atomic values. The following Java program uses the
net.sf.saxon.om.SequenceIterator and
net.sf.saxon.query.QueryResult classes to do this:
/*
The resulted document : C:\Data_Local\xml\docs\wrap.xml
*/
//Java
import java.io.File;
import java.io.OutputStream;
import java.io.FileOutputStream;
import java.util.Properties;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.stream.StreamResult;
//Saxon
import net.sf.saxon.om.SequenceIterator;
import net.sf.saxon.query.QueryResult;
import net.sf.saxon.om.DocumentInfo;
import net.sf.saxon.Configuration;
import net.sf.saxon.query.DynamicQueryContext;
import net.sf.saxon.query.StaticQueryContext;
import net.sf.saxon.query.XQueryExpression;
public class XQueryWrapExample {
public static void main(String[] args) {
XQueryExpression exp=null; //used for compilation
//the XQuery query
String query="for $i in (1, 2,3)"+"return ($i)";
//wrap.xml
String xmlFileName="C://Data_Local//xml//docs//wrap.xml";
File outFile=null;
OutputStream destStream=null;
//create an instance of Configuration
Configuration C=new Configuration();
//create the static and dynamic contexts
StaticQueryContext SQC=new StaticQueryContext(C);
DynamicQueryContext DQC=new DynamicQueryContext(C);
//indentation
Properties props=new Properties();
props.setProperty(OutputKeys.METHOD,"xml");
props.setProperty(OutputKeys.INDENT,"yes");
try{
//"prepare" the wrap.xml
outFile=new File(xmlFileName);
destStream=new FileOutputStream(outFile);
//compile the XQuery query
exp=SQC.compileQuery(query);
SQC=exp.getStaticContext();
}catch(net.sf.saxon.trans.XPathException e)
{System.err.println(e.getMessage());
}catch(java.io.IOException e)
{System.err.println(e.getMessage());}
try{
//execute the query and wrap the result into wrap.xml
SequenceIterator SI=exp.iterator(DQC);
DocumentInfo DI=QueryResult.wrap(SI,C);
QueryResult.serialize(DI,new
StreamResult(destStream),props,C);
destStream.close();
}catch(net.sf.saxon.trans.XPathException e)
{System.err.println(e.getMessage());
}catch(java.io.IOException e)
{System.err.println(e.getMessage());}
}
}
Result:
<?xml version="1.0" encoding="UTF-8"?>
<result:sequence xmlns:result=http://saxon.sf.net/xquery-results
xmlns:xs=http://www.w3.org/2001/XMLSchema
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<result:atomic-value xsi:type="xs:integer">1</result:atomic-value>
<result:atomic-value xsi:type="xs:integer">2</result:atomic-value>
<result:atomic-value xsi:type="xs:integer">3</result:atomic-value>
</result:sequence>
