D-Net

package eu.dnetlib.miscutils.functional.xml;

import java.io.IOException;

import java.io.StringReader;

import java.util.function.UnaryOperator;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.transform.OutputKeys;

import javax.xml.transform.Transformer;

import javax.xml.transform.TransformerFactory;

import javax.xml.transform.dom.DOMSource;

import javax.xml.transform.stream.StreamResult;

import org.apache.commons.io.output.ByteArrayOutputStream;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.w3c.dom.Document;

import org.xml.sax.InputSource;

import org.xml.sax.SAXException;

/**

 * The Class XMLIndenter.

 */

public class XMLIndenter implements UnaryOperator<String> {

	private static final Log log = LogFactory.getLog(XMLIndenter.class);

//	/**

//	 * Static helper Apply.

//	 *

//	 * @param xml the xml

//	 * @return the indented xml string

//	 */

//	public static String indent(final String xml) {

//		return new XMLIndenter().apply(xml);

//	}

//

//	public static String indent(final Document document) throws Exception {

//		return new XMLIndenter().doIndent(document);

//	}

	public String indent(final Document document) throws Exception {

		return doIndent(document);

	}

	/*

	 * (non-Javadoc)

	 *

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

	 */

	@Override

	public String apply(final String unformattedXml) {

		try {

			return doIndent(unformattedXml);

		} catch (Throwable e) {

			return unformattedXml;

		}

	}

	/**

	 * 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 Exception {

		return doIndent(parseXmlString(unformattedXml));

	}

	private String doIndent(final Document document) throws Exception {

		Transformer transformer = TransformerFactory.newInstance().newTransformer();

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

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

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

		final ByteArrayOutputStream out = new ByteArrayOutputStream();

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

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

	}

	/**

	 * Parses the xml string.

	 *

	 * @param in

	 *            the in

	 * @return the document

	 */

	public 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);

		}

	}

}