| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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. |
| */ |
| |
| package org.apache.ambari.server.utils; |
| |
| import java.util.regex.Pattern; |
| |
| /** |
| * HostUtils provides utilities related to processing and validating hosts and host names. |
| */ |
| public class HostUtils { |
| /** |
| * A regular expression to validate that a hostname meets the specifications described in RFC 1123. |
| * <p> |
| * Various sources on the Internet specific this regular expression for hostname validation. |
| */ |
| private static final Pattern REGEX_VALID_HOSTNAME = Pattern.compile("^(?:(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\\-]*[a-zA-Z0-9])\\.)*(?:[A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\\-]*[A-Za-z0-9])$"); |
| |
| /** |
| * Validates a hostname to ensure it meets the specifications described in RFC 1123. |
| * <p> |
| * Note: this does not validate whether the host exists or if the name is a valid DNS name. |
| * For example, host.example.anything is a valid host name however may be an invalid DNS name |
| * since "anything" may not be a valid top-level domain. |
| * |
| * @param hostname a hostname |
| * @return true if the hostname is valid; false otherwise |
| */ |
| public static boolean isValidHostname(String hostname) { |
| return (hostname != null) && REGEX_VALID_HOSTNAME.matcher(hostname).matches(); |
| } |
| } |