Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/*
 * Copyright 2011 the original author or authors.
 *
 * 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.
 */

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    private static final Pattern ROOT_ELEMENT_PATTERN = Pattern.compile("(?:<\\?xml.+?\\?>)?" + // optional prolog
            "(?:\\s*<\\!--.*?-->)*" + // optional comments
            "\\s*<(?:[\\w\\.-]+?:)?([\\w\\.-]+)(?:\\s|(?:/?>))", // open tag of the root element
            Pattern.DOTALL);

    /**
     * Returns local name of the root element of the XML document represented
     * by the given string, or <code>null</code>, when the given string does
     * not contain valid XML.
     * @param s
     *       XML string.
     * @return
     *       root element local name, or <code>null</code> when it could not be determined.
     */
    public static String rootElementName(String s) {
        if (s == null) {
            return null;
        }
        Matcher matcher = ROOT_ELEMENT_PATTERN.matcher(s);
        return (matcher.find() && (matcher.start() == 0)) ? matcher.group(1) : null;
    }
}