content: /*
   * 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.kafka.common.security.kerberos;
  
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  public class KerberosName {
  
      /**
       * A pattern that matches a Kerberos name with at most 3 components.
       */
      private static final Pattern NAME_PARSER = Pattern.compile("([^/@]*)(/([^/@]*))?@([^/@]*)");
  
      /** The first component of the name */
      private final String serviceName;
      /** The second component of the name. It may be null. */
      private final String hostName;
      /** The realm of the name. */
      private final String realm;
  
      /**
       * Creates an instance of `KerberosName` with the provided parameters.
       */
      public KerberosName(String serviceName, String hostName, String realm) {
          if (serviceName == null)
              throw new IllegalArgumentException("serviceName must not be null");
          this.serviceName = serviceName;
          this.hostName = hostName;
          this.realm = realm;
      }
  
      /**
       * Create a name from the full Kerberos principal name.
       */
      public static KerberosName parse(String principalName) {
          Matcher match = NAME_PARSER.matcher(principalName);
          if (!match.matches()) {
              if (principalName.contains("@")) {
                  throw new IllegalArgumentException("Malformed Kerberos name: " + principalName);
              } else {
                  return new KerberosName(principalName, null, null);
              }
          } else {
              return new KerberosName(match.group(1), match.group(3), match.group(4));
          }
      }
  
      /**
       * Put the name back together from the parts.
       */
      @Override
      public String toString() {
          StringBuilder result = new StringBuilder();
          result.append(serviceName);
          if (hostName != null) {
              result.append('/');
              result.append(hostName);
          }
          if (realm != null) {
              result.append('@');
              result.append(realm);
          }
          return result.toString();
      }
  
      /**
       * Get the first component of the name.
       * @return the first section of the Kerberos principal name
       */
      public String serviceName() {
          return serviceName;
      }
  
      /**
       * Get the second component of the name.
       * @return the second section of the Kerberos principal name, and may be null
       */
      public String hostName() {
          return hostName;
      }
  
      /**
       * Get the realm of the name.
       * @return the realm of the name, may be null
       */
      public String realm() {
          return realm;
      }
  
  }
  