URLUtil.java

/*
 * Copyright 1998-2016 Linux.org.ru
 *    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.
 */

/* (C) Max Valjansky,
       Anastasiya Mishechkina 2000
*/

package ru.org.linux.util;

import java.util.regex.Pattern;

public final class URLUtil {
  private static final Pattern isUrl = Pattern.compile(
    "(((https?)|(ftp))://(([0-9\\p{L}.-]+\\.\\p{L}+)|(\\d+\\.\\d+\\.\\d+\\.\\d+))(:[0-9]+)?(/[^ ]*)?)|(mailto:[a-z0-9_+-.]+@[0-9a-z.-]+\\.[a-z]+)|(news:[a-z0-9.-]+)|(((www)|(ftp))\\.(([0-9a-z.-]+\\.[a-z]+(:[0-9]+)?(/[^ ]*)?)|([a-z]+(/[^ ]*)?)))",
    Pattern.CASE_INSENSITIVE
  );

  private URLUtil() {
  }

  public static String fixURL(String url) {
    url = url.trim();

    if (isUrl(url)) {
      if (url.toLowerCase().startsWith("www.")) {
        return "http://" + url;
      }
      if (url.toLowerCase().startsWith("ftp.")) {
        return "ftp://" + url;
      }
      return url;
    }

    return url;
  }

  public static boolean isUrl(String x) {
    return isUrl.matcher(x).matches();
  }
}