Java Utililty Methods XPath Find

List findAll(Node node, String xpath)
Returns a NodeList composed of all the nodes that match an XPath expression, which must be valid.

if (node == null) {
 throw new NullPointerException("node cannot be null.");
try {
 NodeList nodes = (NodeList) xPathEngine.evaluate(xpath, node, XPathConstants.NODESET);
 List<Node> result = new ArrayList<Node>(nodes.getLength());
 for (int i = 0; i < nodes.getLength(); i++) {
 result.add(nodes.item(i));
...

List findAll(Node root, String xPath)
Finds all nodes matching the xPath

List<Node> result = new ArrayList<Node>();
NodeList childNodes;
try {
 childNodes = (NodeList) (xPath(xPath).evaluate(root, XPathConstants.NODESET));
} catch (XPathExpressionException e) {
 throw new IllegalArgumentException("Invalid expression: " + xPath, e);
for (int i = 0; i < childNodes.getLength(); i += 1) {
...

Node findNode(String xPathExpression, Element root)
Checks in under a given root element whether it can find a child node which matches the XPath expression supplied.

if (xPathExpression == null || root == null || xPathExpression.length() == 0) {
 throw new IllegalArgumentException("Xpath expression and root element required");
Node node = null;
try {
 XPathExpression expr = compiledExpressionCache.get(xPathExpression);
 if (expr == null) {
 expr = xpath.compile(xPathExpression);
...

Node findNodeByXPath(Node base, String xpath)
find Node By X Path

if ("/".equals(xpath)) {
 return base;
Node node = base;
StringTokenizer tok = new StringTokenizer(xpath, "/");
while (tok.hasMoreTokens()) {
 String subpath = tok.nextToken();
 String localName;
...

Node findNodeByXpath(String xpathExpression, String fileName)
find Node By Xpath

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setValidating(false);
DocumentBuilder db;
Document doc;
try {
 db = dbf.newDocumentBuilder();
 doc = db.parse(new File(fileName));
 XPath xpath = XPathFactory.newInstance().newXPath();
...

Node findNodeByXPath(String xPathString, Object source)
find Node By X Path

NodeList list = (NodeList) getXPathExpression(xPathString).evaluate(source, XPathConstants.NODESET);
int len = list.getLength();
return len == 0 ? null : list.item(0);

List findNodes(final Node node, final String expression)
find Nodes

final XPath path = xpf.newXPath();
final XPathExpression expr = path.compile(expression);
final NodeList nodeList = (NodeList) expr.evaluate(node, XPathConstants.NODESET);
if (nodeList == null) {
 return Collections.emptyList();
final List<Node> result = new LinkedList<Node>();
for (int i = 0; i < nodeList.getLength(); i++) {
...

NodeList findNodesByXPath(Node contextNode, String expression)
find Nodes By X Path

return (NodeList) XPathFactory.newInstance().newXPath().evaluate(expression, contextNode,
 XPathConstants.NODESET);

NodeList query(Node context, String query)
Performs a xpath query on a document and returns the matching nodelist.

NodeList result = null;
XPath xpath = XPathFactory.newInstance().newXPath();
try {
 result = (NodeList) xpath.evaluate(query, context, XPathConstants.NODESET);
} catch (XPathExpressionException xpx) {
 throw new Exception("Error evaluating XPath: " + xpx.getMessage(), xpx);
return result;
...

String querySingle(Node node, String xpathQuery, final String filePath)
query Single

NodeList list = query(node, xpathQuery, filePath);
int count = list.getLength();
if (count > 1)
 throw new RuntimeException(
 "query " + xpathQuery + " returned " + list.getLength() + " results. Should have been one.");
return count == 1 ? list.item(0).getTextContent() : null;