001/* 002 * Copyright 2015-2020 the original author or authors 003 * 004 * This software is licensed under the Apache License, Version 2.0, 005 * the GNU Lesser General Public License version 2 or later ("LGPL") 006 * and the WTFPL. 007 * You may choose either license to govern your use of this software only 008 * upon the condition that you accept all of the terms of either 009 * the Apache License 2.0, the LGPL 2.1+ or the WTFPL. 010 */ 011package org.minidns.dnslabel; 012 013/** 014 * A reserved LDH label (R-LDH label), which have the property that they contain "--" in the third and fourth characters. 015 * 016 */ 017public class ReservedLdhLabel extends LdhLabel { 018 019 protected ReservedLdhLabel(String label) { 020 super(label); 021 assert isReservedLdhLabelInternal(label); 022 } 023 024 public static boolean isReservedLdhLabel(String label) { 025 if (!isLdhLabel(label)) { 026 return false; 027 } 028 return isReservedLdhLabelInternal(label); 029 } 030 031 static boolean isReservedLdhLabelInternal(String label) { 032 return label.length() >= 4 033 && label.charAt(2) == '-' 034 && label.charAt(3) == '-'; 035 } 036}