XMLIndentUtil.java

package org.wiztools.restclient.util;

import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.bootstrap.DOMImplementationRegistry;
import org.w3c.dom.ls.DOMImplementationLS;
import org.w3c.dom.ls.LSOutput;
import org.w3c.dom.ls.LSSerializer;
import org.wiztools.restclient.persistence.XMLException;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

/**
 *
 * @author subwiz
 */
public final class XMLIndentUtil {
    private XMLIndentUtil() {
    }

    public static String getIndented(String inXml) throws IOException {
        try {
            final InputSource src = new InputSource(new StringReader(inXml));
            final Document domDoc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(src);
            String encoding = domDoc.getXmlEncoding();
            if (encoding == null) {
                // defaults to UTF-8
                encoding = "UTF-8";
            }
            final Node document = domDoc.getDocumentElement();
            final boolean keepDeclaration = inXml.startsWith("<?xml");

            final DOMImplementationRegistry registry = DOMImplementationRegistry.newInstance();
            final DOMImplementationLS impl = (DOMImplementationLS) registry.getDOMImplementation("LS");
            final LSSerializer writer = impl.createLSSerializer();

            writer.setNewLine("\n");
            writer.getDomConfig().setParameter("format-pretty-print", true); // Set this to true if the output needs to be beautified.
            writer.getDomConfig().setParameter("xml-declaration", keepDeclaration); // Set this to true if the declaration is needed to be outputted.

            LSOutput lsOutput = impl.createLSOutput();
            lsOutput.setEncoding(encoding);
            Writer stringWriter = new StringWriter();
            lsOutput.setCharacterStream(stringWriter);
            writer.write(document, lsOutput);

            return stringWriter.toString();
        }
        catch (ParserConfigurationException ex) {
            throw new XMLException(null, ex);
        }
        catch (SAXException ex) {
            throw new XMLException(null, ex);
        }
        catch (ClassNotFoundException ex) {
            throw new XMLException(null, ex);
        }
        catch (InstantiationException ex) {
            throw new XMLException(null, ex);
        }
        catch (IllegalAccessException ex) {
            throw new XMLException(null, ex);
        }
    }

}