| /* |
| * 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.nifi.registry.security.util.kerberos; |
| |
| import org.apache.commons.lang3.StringUtils; |
| |
| public class KerberosPrincipalParser { |
| |
| /** |
| * <p>Determines the realm specified in the given kerberos principal. |
| * |
| * <p>The content of the given {@code principal} after the occurrence |
| * of the last non-escaped realm delimiter ("@") will be considered |
| * the realm of the principal. |
| * |
| * <p>The validity of the given {@code principal} and the determined realm |
| * is not be verified by this method. |
| * |
| * @param principal the principal for which the realm will be determined |
| * @return the realm of the given principal |
| */ |
| public static String getRealm(String principal) { |
| if (StringUtils.isBlank(principal)) { |
| throw new IllegalArgumentException("principal can not be null or empty"); |
| } |
| |
| char previousChar = 0; |
| int realmDelimiterIndex = -1; |
| char currentChar; |
| boolean realmDelimiterFound = false; |
| int principalLength = principal.length(); |
| |
| // find the last non-escaped occurrence of the realm delimiter |
| for (int i = 0; i < principalLength; ++i) { |
| currentChar = principal.charAt(i); |
| if (currentChar == '@' && previousChar != '\\' ) { |
| realmDelimiterIndex = i; |
| realmDelimiterFound = true; |
| } |
| previousChar = currentChar; |
| } |
| |
| String principalAfterLastRealmDelimiter = principal.substring(realmDelimiterIndex + 1); |
| return realmDelimiterFound && realmDelimiterIndex + 1 < principalLength ? principalAfterLastRealmDelimiter : null; |
| } |
| } |