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.activemq.shiro.authc;
  
  import org.apache.activemq.shiro.subject.SubjectConnectionReference;
  import org.apache.shiro.authc.AuthenticationToken;
  
  /**
   * A {@code AuthenticationTokenFactory} inspects a newly-added ActiveMQ connection and returns a Shiro
   * {@link AuthenticationToken} instance representing credentials associated with the connection.  These credentials can
   * be used to {@link org.apache.shiro.subject.Subject#login(org.apache.shiro.authc.AuthenticationToken) authenticate}
   * the connection, allowing for later identity and authorization (access control) checks.
   *
   * @see AuthenticationFilter#addConnection(org.apache.activemq.broker.ConnectionContext, org.apache.activemq.command.ConnectionInfo)
   * @since 5.10.0
   */
  public interface AuthenticationTokenFactory {
  
      /**
       * Returns a Shiro {@code AuthenticationToken} instance that should be used to authenticate the connection's
       * {@link org.apache.shiro.subject.Subject}, or {@code null} if no authentication information can be obtained.
       * <p/>
       * If no {@code AuthenticationToken} can be obtained, the connection's Subject will be considered anonymous and any
       * downstream security checks that enforce authentication or authorization will fail (as would be expected).
       *
       * @param ref the subject's connection
       * @return a Shiro {@code AuthenticationToken} instance that should be used to authenticate the connection's
       *         {@link org.apache.shiro.subject.Subject}, or {@code null} if no authentication information can be obtained.
       * @throws Exception if there is a problem acquiring/creating an expected {@code AuthenticationToken}.
       */
      AuthenticationToken getAuthenticationToken(SubjectConnectionReference ref) throws Exception;
  }
  