Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;

import java.util.HashMap;

import java.util.Map;

import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Element;
import org.w3c.dom.Node;

public class Main {
    private static final Map<String, XPathExpression> COMPILED_EXPRESSION_CACHE = new HashMap<String, XPathExpression>();
    private static final XPath XPATH = XPathFactory.newInstance().newXPath();

    /**
     * Checks for a given element whether it can find an attribute which matches
     * the XPath expression supplied. Returns {@link Node} if exists.
     * 
     * @param xPathExpression the xPathExpression (required)
     * @param element (required)
     * @return the Node if discovered (null if not found)
     */
    public static Node findFirstAttribute(final String xPathExpression, final Element element) {
        Node attr = null;
        try {
            XPathExpression expr = COMPILED_EXPRESSION_CACHE.get(xPathExpression);
            if (expr == null) {
                expr = XPATH.compile(xPathExpression);
                COMPILED_EXPRESSION_CACHE.put(xPathExpression, expr);
            }
            attr = (Node) expr.evaluate(element, XPathConstants.NODE);
        } catch (final XPathExpressionException e) {
            throw new IllegalArgumentException("Unable evaluate xpath expression", e);
        }
        return attr;
    }
}