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.bookkeeper.auth;
  
  import java.io.IOException;
  import org.apache.bookkeeper.conf.ClientConfiguration;
  import org.apache.bookkeeper.proto.ClientConnectionPeer;
  
  /**
   * Client authentication provider interface.
   * This must be implemented by any party wishing to implement
   * an authentication mechanism for bookkeeper connections.
   */
  public interface ClientAuthProvider {
      /**
       * A factory to create the authentication providers for bookkeeper clients.
       */
      interface Factory {
          /**
           * Initialize the factory with the client configuration
           * and protobuf message registry. Implementors must
           * add any extension messages which contain the auth
           * payload, so that the client can decode auth messages
           * it receives from the server.
           */
          void init(ClientConfiguration conf) throws IOException;
  
          /**
           * Create a new instance of a client auth provider.
           * Each connection should get its own instance, as they
           * can hold connection specific state.
           * The completeCb is used to notify the client that
           * the authentication handshake is complete.
           * CompleteCb should be called only once.
           * If the authentication was successful, BKException.Code.OK
           * should be passed as the return code. Otherwise, another
           * error code should be passed.
           * @param connection an handle to the connection
           * @param completeCb callback to be notified when authentication
           *                   is complete.
           */
          ClientAuthProvider newProvider(ClientConnectionPeer connection,
                                         AuthCallbacks.GenericCallback<Void> completeCb);
  
          /**
           * Get Auth provider plugin name.
           * Used as a sanity check to ensure that the bookie and the client.
           * are using the same auth provider.
           */
          String getPluginName();
  
          /**
          * Release resources.
          */
          default void close() {}
      }
  
      /**
       * Initiate the authentication. cb will receive the initial
       * authentication message which should be sent to the server.
       * cb may not be called if authentication is not requires. In
       * this case, completeCb should be called.
       */
      void init(AuthCallbacks.GenericCallback<AuthToken> cb);
  
      /**
       * Callback to let the provider know that the underlying protocol is changed.
       * For instance this will happen when a START_TLS operation succeeds
       */
      default void onProtocolUpgrade() {
      }
  
      /**
       * Process a response from the server. cb will receive the next
       * message to be sent to the server. If there are no more messages
       * to send to the server, cb should not be called, and completeCb
       * must be called instead.
       */
      void process(AuthToken m, AuthCallbacks.GenericCallback<AuthToken> cb);
  
      /**
       * Release resources.
       */
      default void close() {}
  }
  