D-Net

package eu.dnetlib.miscutils.functional.xml;

import java.io.*;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.transform.*;

import javax.xml.transform.dom.DOMResult;

import javax.xml.transform.dom.DOMSource;

import javax.xml.transform.stream.StreamResult;

import com.sun.org.apache.xml.internal.serialize.OutputFormat;

import com.sun.org.apache.xml.internal.serialize.XMLSerializer;

import eu.dnetlib.miscutils.functional.UnaryFunction;

import org.w3c.dom.Document;

import org.xml.sax.InputSource;

import org.xml.sax.SAXException;

/**

 * The Class IndentXmlString.

 */

public class IndentXmlString implements UnaryFunction<String, String> {

	/*

	 * (non-Javadoc)

	 * 

	 * @see eu.dnetlib.miscutils.functional.UnaryFunction#evaluate(java.lang.Object)

	 */

	@Override

	public String evaluate(final String unformattedXml) {

		try {

			return doIndent(unformattedXml);

		} catch (IOException e) {

			throw new RuntimeException(e);

		}

	}

	/**

	 * Do indent.

	 * 

	 * @param unformattedXml

	 *            the unformatted xml

	 * @return the string

	 * @throws IOException

	 *             Signals that an I/O exception has occurred.

	 */

	protected String doIndent(final String unformattedXml) throws IOException {

		final Document document = parseXmlString(unformattedXml);

		OutputFormat format = new OutputFormat(document);

		format.setIndenting(true);

		format.setIndent(2);

		Writer out = new StringWriter();

		XMLSerializer serializer = new XMLSerializer(out, format);

		serializer.serialize(document);

		return out.toString();

	}

	/**

	 * Parses the xml string.

	 * 

	 * @param in

	 *            the in

	 * @return the document

	 */

	protected Document parseXmlString(final String in) {

		try {

			DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

			DocumentBuilder db = dbf.newDocumentBuilder();

			db.setErrorHandler(null);

			InputSource is = new InputSource(new StringReader(in));

			return db.parse(is);

		} catch (ParserConfigurationException e) {

			throw new RuntimeException(e);

		} catch (SAXException e) {

			throw new RuntimeException(e);

		} catch (IOException e) {

			throw new RuntimeException(e);

		}

	}

	private String doIndent(final Document document) throws TransformerException, UnsupportedEncodingException {

		final Transformer transformer = getTransformer();

		final ByteArrayOutputStream out = new ByteArrayOutputStream();

		transformer.transform(new DOMSource(document), new StreamResult(out));

		return out.toString("utf-8");

	}

	private Transformer getTransformer() throws TransformerConfigurationException {

		TransformerFactory tf = TransformerFactory.newInstance();

		Transformer transformer = tf.newTransformer();

		transformer.setOutputProperty(OutputKeys.INDENT, "yes");

		transformer.setOutputProperty(OutputKeys.DOCTYPE_PUBLIC, "yes");

		transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");

		return transformer;

	}

	private Document doIndentDocument(final Document document) throws TransformerException, UnsupportedEncodingException {

		final Transformer transformer = getTransformer();

		final DOMResult out = new DOMResult();

		transformer.transform(new DOMSource(document), out);

		return (Document) out.getNode();

	}

	/**

	 * Static helper Apply.

	 * 

	 * @param xml

	 *            the xml

	 * @return the indented xml string

	 */

	public static String apply(final String xml) {

		return new IndentXmlString().evaluate(xml);

	}

	/**

	 * Static helper Apply.

	 *

	 * @param xml

	 *            the xml

	 * @return the indented xml string

	 */

	public static Document apply(final Document xml) throws TransformerException, UnsupportedEncodingException {

		return new IndentXmlString().doIndentDocument(xml);

	}

}