package com.kodcu.other;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.xml.sax.Attributes;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import javax.xml.parsers.*;
import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Stack;
/**
* Created by usta on 20.09.2015.
*/
public class PositionalXMLReader {
final static String LINE_NUMBER_KEY_NAME = "lineNumber";
public static Document readXML(final Document inDocument) throws Exception {
SAXParser parser;
Document outDocument;
try {
final SAXParserFactory factory = SAXParserFactory.newInstance();
parser = factory.newSAXParser();
final DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
final DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
outDocument = docBuilder.newDocument();
} catch (final ParserConfigurationException e) {
throw new RuntimeException("Can't create SAX parser / DOM builder.", e);
}
final Stack<Element> elementStack = new Stack<Element>();
final StringBuilder textBuffer = new StringBuilder();
final DefaultHandler handler = new DefaultHandler() {
private Locator locator;
@Override
public void setDocumentLocator(final Locator locator) {
this.locator = locator; // Save the locator, so that it can be used later for line tracking when traversing nodes.
}
@Override
public void startElement(final String uri, final String localName, final String qName, final Attributes attributes)
throws SAXException {
addTextIfNeeded();
final Element el = outDocument.createElement(qName);
for (int i = 0; i < attributes.getLength(); i++) {
el.setAttribute(attributes.getQName(i), attributes.getValue(i));
}
el.setUserData(LINE_NUMBER_KEY_NAME, String.valueOf(this.locator.getLineNumber()), null);
elementStack.push(el);
}
@Override
public void endElement(final String uri, final String localName, final String qName) {
addTextIfNeeded();
final Element closedEl = elementStack.pop();
if (elementStack.isEmpty()) { // Is this the root element?
outDocument.appendChild(closedEl);
} else {
final Element parentEl = elementStack.peek();
parentEl.appendChild(closedEl);
}
}
@Override
public void characters(final char ch[], final int start, final int length) throws SAXException {
textBuffer.append(ch, start, length);
}
// Outputs text accumulated under the current node
private void addTextIfNeeded() {
if (textBuffer.length() > 0) {
final Element el = elementStack.peek();
final Node textNode = outDocument.createTextNode(textBuffer.toString());
el.appendChild(textNode);
textBuffer.delete(0, textBuffer.length());
}
}
};
try (ByteArrayInputStream is = nodeToInputStream(inDocument);) {
parser.parse(is, handler);
}
return outDocument;
}
private static ByteArrayInputStream nodeToInputStream(Node node) throws TransformerException, IOException {
ByteArrayInputStream inputStream;
try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream();) {
Result outputTarget = new StreamResult(outputStream);
Transformer t = TransformerFactory.newInstance().newTransformer();
t.transform(new DOMSource(node), outputTarget);
inputStream = new ByteArrayInputStream(outputStream.toByteArray());
}
return inputStream;
}
}