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.transport.amqp.client.sasl;
  
  import java.util.Map;
  
  import javax.security.sasl.SaslException;
  
  /**
   * Interface for all SASL authentication mechanism implementations.
   */
  public interface Mechanism extends Comparable<Mechanism> {
  
      /**
       * Relative priority values used to arrange the found SASL
       * mechanisms in a preferred order where the level of security
       * generally defines the preference.
       */
      public enum PRIORITY {
          LOWEST(0),
          LOW(1),
          MEDIUM(2),
          HIGH(3),
          HIGHEST(4);
  
          private final int value;
  
          private PRIORITY(int value) {
              this.value = value;
          }
  
          public int getValue() {
              return value;
         }
      };
  
      /**
       * @return return the relative priority of this SASL mechanism.
       */
      int getPriority();
  
      /**
       * @return the well known name of this SASL mechanism.
       */
      String getName();
  
      /**
       * @return the response buffer used to answer the initial SASL cycle.
       * @throws SaslException if an error occurs computing the response.
       */
      byte[] getInitialResponse() throws SaslException;
  
      /**
       * Create a response based on a given challenge from the remote peer.
       *
       * @param challenge
       *        the challenge that this Mechanism should response to.
       *
       * @return the response that answers the given challenge.
       * @throws SaslException if an error occurs computing the response.
       */
      byte[] getChallengeResponse(byte[] challenge) throws SaslException;
  
      /**
       * Sets the user name value for this Mechanism.  The Mechanism can ignore this
       * value if it does not utilize user name in it's authentication processing.
       *
       * @param username
       *        The user name given.
       */
      void setUsername(String value);
  
      /**
       * Returns the configured user name value for this Mechanism.
       *
       * @return the currently set user name value for this Mechanism.
       */
      String getUsername();
  
      /**
       * Sets the password value for this Mechanism.  The Mechanism can ignore this
       * value if it does not utilize a password in it's authentication processing.
       *
       * @param username
       *        The user name given.
       */
      void setPassword(String value);
  
      /**
       * Returns the configured password value for this Mechanism.
       *
       * @return the currently set password value for this Mechanism.
       */
      String getPassword();
  
      /**
       * Sets any additional Mechanism specific properties using a Map<String, Object>
       *
       * @param options
       *        the map of additional properties that this Mechanism should utilize.
       */
      void setProperties(Map<String, Object> options);
  
      /**
       * The currently set Properties for this Mechanism.
       *
       * @return the current set of configuration Properties for this Mechanism.
       */
      Map<String, Object> getProperties();
  
      /**
       * Using the configured credentials, check if the mechanism applies or not.
       *
       * @param username
       *      The user name that will be used with this mechanism
       * @param password
       *      The password that will be used with this mechanism
       *
       * @return true if the mechanism works with the provided credentials or not.
       */
      boolean isApplicable(String username, String password);
  
      /**
       * Get the currently configured Authentication ID.
       *
       * @return the currently set Authentication ID.
       */
      String getAuthzid();
  
      /**
       * Sets an Authentication ID that some mechanism can use during the
       * challenge response phase.
       *
       * @param authzid
       *      The Authentication ID to use.
       */
      void setAuthzid(String authzid);
  
  }
  