Cutting xml parts with StAX and process them with XSLT

Question

I'm trying to cut a xml into parts and then apply it some transformations. Currently I have this code:

    public class XMLStax_xslt {

        static boolean allowStream = false;

        public static void main(String[] args) throws Exception {
            FileInputStream fis = new FileInputStream("SourceExternalFile.xml");        
            XMLInputFactory xmlif = null;
            xmlif = XMLInputFactory.newInstance();
            Source xslt = new StreamSource(new File("myTransformFile.xslt"));

            StreamFilter filter = new StreamFilter() {
                @Override
                public boolean accept(XMLStreamReader reader) {
                    int eventType = reader.getEventType();

                    if ( eventType == XMLEvent.START_ELEMENT )
                    {
                        String currentTag = reader.getLocalName();
                        if (currentTag.equals("wantedTag"))
                        {
                            allowStream = true;
                        }
                    }
                    if ( eventType == XMLEvent.END_ELEMENT )
                    {
                        String currentTag = reader.getLocalName();
                        if (currentTag.equals("wantedTag"))
                        {
                            allowStream = false;
                        }
                    }               
                    return allowStream;
                }
            };
            XMLStreamReader xmlR = xmlif.createFilteredReader(xmlif.createXMLStreamReader(fis),filter);
            while (xmlR.hasNext())
            {
                TransformerFactory transformerXSLT = TransformerFactory.newInstance();
                Transformer currentXslt = transformerXSLT.newTransformer(xslt);
                currentXslt.transform(new StAXSource(xmlR), new StreamResult("targetFile.xml"));
            }        
            fis.close();
        }   
    }

Which works when the line return allowStream; is changed to return true;. So, what I need is send only the part I need to the transformation because sending the whole XML is not an option.

How can I achieve that?

Thanks.

Answer 1

The trouble was that I was passing the string to the transformer, instead of the whole node. Changing XMLStreamReader by XMLEventReader does the trick.

Here's the change:

    public static void main(String[] args) throws Exception {
            FileInputStream fis = new FileInputStream("SourceExternalFile.xml");        
            XMLInputFactory xmlif = null;
            xmlif = XMLInputFactory.newInstance();
            Source xslt = new StreamSource(new File("myTransformFile.xslt"));

            XMLEventReader xmlR = xmlif.createXMLEventReader(xmlif.createXMLStreamReader(fis));

            TransformerFactory transformerXSLT = TransformerFactory.newInstance();
            Transformer currentXslt = transformerXSLT.newTransformer(xslt);

            while (xmlR.hasNext())
            {
                XMLEvent xmlEvent = xmlR.nextEvent();
                if ( xmlEvent.equals("wantedTag") )
                {
                    currentXslt.transform(new StAXSource(xmlR), new StreamResult("targetFile.xml"));
                }
            }
            xmlR.close();
            fis.close();
        }