Main.java Source code

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Here is the source code for Main.java

Source

//package com.java2s;
/**
 * Copyright (C) 2010 http://flowas.net/
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * You can write to flowas@gmial.com for more customer requirement.
 */

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> compiledExpressionCache = 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(String xPathExpression, Element element) {
        Node attr = null;
        try {
            XPathExpression expr = compiledExpressionCache.get(xPathExpression);
            if (expr == null) {
                expr = xpath.compile(xPathExpression);
                compiledExpressionCache.put(xPathExpression, expr);
            }
            attr = (Node) expr.evaluate(element, XPathConstants.NODE);
        } catch (XPathExpressionException e) {
            throw new IllegalArgumentException("Unable evaluate xpath expression", e);
        }
        return attr;
    }
}