Java tutorial
//package com.java2s; /* * aTunes * Copyright (C) Alex Aranda, Sylvain Gaudard and contributors * * See http://www.atunes.org/wiki/index.php?title=Contributing for information about contributors * * http://www.atunes.org * http://sourceforge.net/projects/atunes * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ import javax.xml.xpath.XPath; import javax.xml.xpath.XPathConstants; import javax.xml.xpath.XPathExpressionException; import javax.xml.xpath.XPathFactory; import org.w3c.dom.Node; import org.w3c.dom.NodeList; public class Main { private static volatile ThreadLocal<XPath> xPath; /** * Evaluates a XPath expression from a XML node, returning a NodeList. * * @param expression * A XPath expression * @param node * The NodeList for which this expression should be evaluated * * @return The result of evaluating the XPath expression to the given or * <code>null</code> if an ecxception occured NodeList */ public static NodeList evaluateXPathExpressionAndReturnNodeList(String expression, Node node) { try { return (NodeList) getXPath().get().evaluate(expression, node, XPathConstants.NODESET); } catch (XPathExpressionException e) { return null; } } private static ThreadLocal<XPath> getXPath() { if (xPath == null) { xPath = new ThreadLocal<XPath>() { @Override protected XPath initialValue() { return XPathFactory.newInstance().newXPath(); } }; } return xPath; } }