DOM4J: configure sax reader to remove ns uris

XMLNSFilter.java

package com.cliff.xmlns;

import org.dom4j.Document;
import org.dom4j.DocumentFactory;
import org.dom4j.Node;
import org.dom4j.XPath;
import org.dom4j.io.SAXReader;
import org.junit.Before;
import org.junit.Test;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLFilterImpl;
import org.xml.sax.helpers.XMLReaderFactory;

import java.io.File;

import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.fail;

public class DOM4JXmlNsTest {
    private SAXReader saxReader;
    private Document document;

    private class NamespaceStrippingFilter extends XMLFilterImpl {
        @Override
        public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

            super.startElement(null, localName, localName, attributes);
        }

        @Override
        public void endElement(String uri, String localName, String qName) throws SAXException {
            super.endElement(null, localName, localName);
        }

    }

    @Before
    public void setup() throws Exception {
        XMLReader saxXmlReader;
        try {
            saxXmlReader = XMLReaderFactory.createXMLReader(
                    "org.apache.xerces.parsers.SAXParser"
            );
            System.out.println("Successfully found Xerces parser!");
        }
        catch (SAXException e) {
            try {
                saxXmlReader = XMLReaderFactory.createXMLReader();
                System.out.println("Falling back to default SAX Reader: " + saxXmlReader.getClass().getName());
            }
            catch (SAXException e2) {
                throw new NoClassDefFoundError("No SAX parser is available");
                // or whatever exception your method is declared to throw
            }
        }

        NamespaceStrippingFilter filter = new NamespaceStrippingFilter();
        filter.setParent(saxXmlReader);
        //DocumentFactory.getInstance().setXPathNamespaceURIs(nsMap);
        saxReader = new SAXReader(saxXmlReader, false);
        saxReader.setXMLFilter(filter);
    }

    public Document readDoc(String path) {
        try {
            return saxReader.read(new File(path));
        } catch(Exception ex) {
            fail("Caught exception trying to read: "+path);
        }
        return null;
    }

    @Test
    public void testNSXml()  {
        document = readDoc("src/test/resources/example1.xml");
        assertNotNull(document);
        Node n = document.selectSingleNode("html/body/bookreview");
        System.out.println(n.asXML());
    }

    @Test
    public void testNoNSXml() {
        document = readDoc("src/test/resources/example1-overriden-rootns.xml");
        assertNotNull(document);
        Node n = document.selectSingleNode("html/body/bookreview");
        System.out.println(n.asXML());

    }

    @Test
    public void perfTest() {
        XPath compiledXpath = DocumentFactory.getInstance().createXPath("html/body/bookreview");
        int iterations = 3000;
        long start = System.currentTimeMillis();
        Node n = null;
        for(int i=0; i<iterations; i++) {
            document = readDoc("src/test/resources/example1.xml");
            //n = compiledXpath.selectSingleNode(document);
            //if (n == null)
              //  fail("Xpath selected no nodes!");
            //System.out.println(n.asXML());
        }
        long elapsedTime = System.currentTimeMillis()-start;
        double avgTime = elapsedTime/iterations;
        System.out.println(String.format("%d iterations in %d ms, avgTime: %5.2f ms, docsPerSec: %5.2f",
                iterations,
                elapsedTime,
                avgTime,
                1000/avgTime));
    }


}