Do I understand the task correctly?

package com.codegym.task.task33.task3309; /* Comments inside XML */ /* approaches: 1. (probably easy) marshall into a String, search the string for the tag, replace tag with comment + tag -> coded this, but I think it does not meet all requirements as it does not add CDATA ==> dropped that approach 2. from the comments to this task: marshall into a DOM, loop over the nodes, change to CDATA and add comments if necessary */ import org.w3c.dom.*; import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBException; import javax.xml.bind.Marshaller; import javax.xml.bind.annotation.XmlRootElement; import javax.xml.bind.annotation.XmlType; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.transform.*; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult; import java.io.StringWriter; public class Solution { public static String toXmlWithComment(Object obj, String tagName, String comment) { Document document = null; try { // first create the document and read the object as XML into it document = createXMLDocument(); marshalXMLIntoDocument(obj, document); // now find the nodes matching tagName using Document.getElementsByTagName() // then loop through the resulting NodeList to get Nodes and add comments to that nodes NodeList nodeList = document.getElementsByTagName(tagName); for (int i = 0; i < nodeList.getLength(); i++) { // currentNode is the current iteration's node matching tagName, before that we insert the comment Node currentNode = nodeList.item(i); currentNode.getParentNode().insertBefore(document.createComment(comment), currentNode); // requirement: The XML serialization of obj may contain CDATA sections with the specified tag. Don't add comments before them. // So I walked through the DOM and found that there is no CDATA inside, just TEXT. Having eg. // <![CDATA[<div>My text</div>]]> inside a String to marshall just adds TEXT to the DOM. // at this point, when adding the comments I already found the tagNames in question. Now I check the current // tags TEXT if it contains escape chars <>&'" and if so i create a CDATA before the current node with TEXT as content String nodeText = currentNode.getTextContent(); if (nodeText.matches(".*[<>&'\"].*")) { // contains escape char, then resave as CDATA currentNode.setTextContent(""); // needs to be set to empty before appending the CDATA, otherwise no CDATA gets added currentNode.appendChild(document.createCDATASection(nodeText)); // as a result I get a CDATA field wrapped around the former tag's text instead of the text } } return transformDocumentToString(document); } catch (JAXBException | ParserConfigurationException | TransformerException e) { throw new RuntimeException(e); } } /** * uses Transformer to convert the Document into a String () * * @param document * @return * @throws TransformerException */ public static String transformDocumentToString(Document document) throws TransformerException { StringWriter sw = new StringWriter(); // create a Transformer and pass it a DomSource, the document and a Result, the StringWriter Transformer tf = TransformerFactory.newInstance().newTransformer(); // set indentation to true tf.setOutputProperty(OutputKeys.INDENT, "yes"); tf.transform(new DOMSource(document), new StreamResult(sw)); return sw.toString(); } /** * Used to read obj data into a Document as XML using JAXB marshalling * * @param obj * @param document * @throws JAXBException */ public static void marshalXMLIntoDocument(Object obj, Document document) throws JAXBException { JAXBContext context = JAXBContext.newInstance(obj.getClass()); Marshaller marshaller = context.createMarshaller(); // marshall directly into the document marshaller.marshal(obj, document); } /** * creates an empty w3c Document using DocumentBuilderFactory and DocumentBuilder to hold HTML or XML DOMs * * @return * @throws ParserConfigurationException */ public static Document createXMLDocument() throws ParserConfigurationException { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db = dbf.newDocumentBuilder(); return db.newDocument(); } /** * main method to test toXmlWithComment() * * @param args * @throws Exception */ public static void main(String[] args) throws Exception { SampleData sampleData = new SampleData(); System.out.println(toXmlWithComment(sampleData, "list", "sample comment")); System.out.println(toXmlWithComment(sampleData, "notExistingTag", "sample comment")); } /** * inner class used to convert to xml */ @XmlType(name = "sampleData") @XmlRootElement public static class SampleData { // first elements contains escape chars, so this should be added as CDATA not TEXT // second element is empty, don't display any content // third element contains no escape chars, display as TEXT public String[] list = new String[]{"add as CDATA, <&'\">", "", "noCdata here"}; } }