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 com.datastax.oss.driver.api.core.auth;
  
  import com.datastax.oss.driver.api.core.connection.ReconnectionPolicy;
  import com.datastax.oss.driver.api.core.metadata.EndPoint;
  import com.datastax.oss.driver.internal.core.auth.PlainTextAuthProvider;
  import edu.umd.cs.findbugs.annotations.NonNull;
  
  /**
   * Provides {@link Authenticator} instances to use when connecting to Cassandra nodes.
   *
   * <p>See {@link PlainTextAuthProvider} for an implementation which uses SASL PLAIN mechanism to
   * authenticate using username/password strings.
   */
  public interface AuthProvider extends AutoCloseable {
  
    /**
     * The authenticator to use when connecting to {@code host}.
     *
     * @param endPoint the Cassandra host to connect to.
     * @param serverAuthenticator the configured authenticator on the host.
     * @return the authentication implementation to use.
     */
    @NonNull
    Authenticator newAuthenticator(@NonNull EndPoint endPoint, @NonNull String serverAuthenticator)
        throws AuthenticationException;
  
    /**
     * What to do if the server does not send back an authentication challenge (in other words, lets
     * the client connect without any form of authentication).
     *
     * <p>This is suspicious because having authentication enabled on the client but not on the server
     * is probably a configuration mistake.
     *
     * <p>Provider implementations are free to handle this however they want; typical approaches are:
     *
     * <ul>
     *   <li>ignoring;
     *   <li>logging a warning;
     *   <li>throwing an {@link AuthenticationException} to abort the connection (but note that it
     *       will be retried according to the {@link ReconnectionPolicy}).
     * </ul>
     */
    void onMissingChallenge(@NonNull EndPoint endPoint) throws AuthenticationException;
  }
  