How to use XmlModify to sort the XML Data?

Question

Hello,
I saw some examples explain how to use XmlModify in BDB XML package. I want to sort the XML data by several elements but my Java program could not work correctly.
<CustomerData>
<Transaction>
<DLSFIELDS>
<ADR_PST_CD>12345</ADR_PST_CD>
<CLT_IRD_NBR>002</CLT_IRD_NBR>
</DLSFIELDS>
</Transaction>
<Transaction>
<DLSFIELDS>
<ADR_PST_CD>12345</ADR_PST_CD>
<CLT_IRD_NBR>102</CLT_IRD_NBR>
</DLSFIELDS>
</Transaction>
// many nodes like transaction ...
</CustomerData>
My XQuery script was executed successfully in the shell. The script looks as follows:
"for $i in collection('sample.dbxml')/CustomerData/Transaction order by xs:decimal($i//ADR_PST_CD), xs:decimal($i//CLT_IRD_NBR) return $i".
The Java code :
// create XmlManager
XmlManager manager = // ...;
// open XmlContainer
XmlContainer container = // ...;
XmlQueryContext context = manager.createQueryContext(XmlQueryContext.LiveValues, XmlQueryContext.Eager);
XmlQueryExpression expression = manager.prepare("for $i in collection('sample.dbxml')/CustomerData/Transaction order by xs:decimal($i//ADR_PST_CD),xs:decimal($i//CLT_IRD_NBR) return $i", context);
XmlModify modify = manager.createModify();
XmlUpdateContext uc = manager.createUpdateContext();
XmlDocument xmldoc = container.getDocument("sample.xml");
XmlValue value = new XmlValue(xmldoc);
long numMod = modify.execute(value, context, uc);
System.out.println("Peformed " + numMod     + " modification operations");
Could you point out the errors above or offer some suggestion?
Thanks.

Answer 1

I have other question of the sorting issue. Here are a large XML need to sort so I have to split it to multiple small XML files. After importing these files, I will use the XmlModify and XQuery to sort them. I'm not clear on the multiple XML files processing.
1. Can the BDB XML ensure that all these XML files were sorted or how to update all documents with same logic.
2. If I want export all these sorted documents, how can I ensure these files processed in sequence? Which document needs process first?
The export method:
public void export(String outputfile)throws Exception{
final int BLOCK_SIZE = 5 * 1024 * 1024; // 5Mb
try{
File theFile = new File(outputfile);
FileOutputStream fos = new FileOutputStream(theFile);
byte[] buff= new byte[BLOCK_SIZE];                         
XmlResults rs = container.getAllDocuments(new XmlDocumentConfig());               
while(rs.hasNext()){
     XmlDocument xmlDoc = rs.next().asDocument();
     XmlInputStream inputStream = xmlDoc.getContentAsXmlInputStream();                    
     long read=0;
     while(true){
     read = inputStream.readBytes(buff, BLOCK_SIZE);
fos.write(buff,0,(int)read);                    
     if(read < BLOCK_SIZE) break;
inputStream.delete();
xmlDoc.delete();
rs.delete();
//MUST CLOSE!
fos.close();               
catch(Exception e){
System.err.println("Error exporting file from container " + container);
System.err.println(" Message: " + e.getMessage());
Thanks.