Generate/get xpath from XML node java

Question

I\'m interested in advice/pseudocode code/explanation rather than actual implementation.

• I\'d like to go trough xml document

Answer 1

Here is how this can be done with SAX:

import java.util.HashMap;
import java.util.Map;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

public class FragmentContentHandler extends DefaultHandler {

    private String xPath = "/";
    private XMLReader xmlReader;
    private FragmentContentHandler parent;
    private StringBuilder characters = new StringBuilder();
    private Map elementNameCount = new HashMap();

    public FragmentContentHandler(XMLReader xmlReader) {
        this.xmlReader = xmlReader;
    }

    private FragmentContentHandler(String xPath, XMLReader xmlReader, FragmentContentHandler parent) {
        this(xmlReader);
        this.xPath = xPath;
        this.parent = parent;
    }

    @Override
    public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException {
        Integer count = elementNameCount.get(qName);
        if(null == count) {
            count = 1;
        } else {
            count++;
        }
        elementNameCount.put(qName, count);
        String childXPath = xPath + "/" + qName + "[" + count + "]";

        int attsLength = atts.getLength();
        for(int x=0; x 0) {
            System.out.println(xPath + "='" + characters.toString() + "'");
        }
        xmlReader.setContentHandler(parent);
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        characters.append(ch, start, length);
    }

}

It can be tested with:

import java.io.FileInputStream;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;

public class Demo {

    public static void main(String[] args) throws Exception {
        SAXParserFactory spf = SAXParserFactory.newInstance();
        SAXParser sp = spf.newSAXParser();
        XMLReader xr = sp.getXMLReader();

        xr.setContentHandler(new FragmentContentHandler(xr));
        xr.parse(new InputSource(new FileInputStream("input.xml")));
    }
}

This will produce the desired output:

//root[1]/elemA[1]='one'
//root[1]/elemA[2][@attribute1='first]
//root[1]/elemA[2][@attribute2='second]
//root[1]/elemA[2]='two'
//root[1]/elemB[1]='three'
//root[1]/elemA[3]='four'
//root[1]/elemC[1]/elemB[1]='five'