Create XML Nodes based on XPath?

Question

Does anyone know of an existing means of creating an XML hierarchy programatically from an XPath expression?

For example if I have an XML fragment such as:

Answer 1

I know this is a really old thread ... but I have just been trying the same thing and came up with the following regex which is not perfect but I find more generic

/+([\w]+)(\[@([\w]+)='([^']*)'\])?|/@([\w]+)

The string /configuration/appSettings/add[@key='name']/@value

should be parsed to

Found 14 match(es):

start=0, end=14 Group(0) = /configuration Group(1) = configuration Group(2) = null Group(3) = null Group(4) = null Group(5) = null

start=14, end=26 Group(0) = /appSettings Group(1) = appSettings Group(2) = null Group(3) = null Group(4) = null Group(5) = null

start=26, end=43 Group(0) = /add[@key='name'] Group(1) = add Group(2) = [@key='name'] Group(3) = key Group(4) = name Group(5) = null

start=43, end=50 Group(0) = /@value Group(1) = null Group(2) = null Group(3) = null Group(4) = null Group(5) = value

---

Which means we have

Group(0) = Ignored Group(1) = The element name Group(2) = Ignored Group(3) = Filter attribute name Group(4) = Filter attribute value

Here is a java method which can use the pattern

public static Node createNodeFromXPath(Document doc, String expression) throws XPathExpressionException {
StringBuilder currentPath = new StringBuilder();
Matcher matcher = xpathParserPattern.matcher(expression);

Node currentNode = doc.getFirstChild();

while (matcher.find()) {
    String currentXPath = matcher.group(0);
    String elementName = matcher.group(1);
    String filterName = matcher.group(3);
    String filterValue = matcher.group(4);
    String attributeName = matcher.group(5);

    StringBuilder builder = currentPath.append(currentXPath);
    String relativePath = builder.toString();
    Node newNode = selectSingleNode(doc, relativePath);

    if (newNode == null) {
        if (attributeName != null) {
            ((Element) currentNode).setAttribute(attributeName, "");
            newNode = selectSingleNode(doc, relativePath);

        } else if (elementName != null) {
            Element element = doc.createElement(elementName);
            if (filterName != null) {
                element.setAttribute(filterName, filterValue);
            }
            currentNode.appendChild(element);
            newNode = element;

        } else {
            throw new UnsupportedOperationException("The given xPath is not supported " + relativePath);
        }
    }

    currentNode = newNode;
}

if (selectSingleNode(doc, expression) == null) {
    throw new IllegalArgumentException("The given xPath cannot be created " + expression);
}

return currentNode;

}