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.dse.driver.api.core.auth;
  
  import com.datastax.oss.driver.api.core.auth.SyncAuthenticator;
  import edu.umd.cs.findbugs.annotations.NonNull;
  import edu.umd.cs.findbugs.annotations.Nullable;
  import java.nio.ByteBuffer;
  import net.jcip.annotations.ThreadSafe;
  
  /**
   * Base class for {@link SyncAuthenticator} implementations that want to make use of the
   * authentication scheme negotiation in <code>DseAuthenticator</code>.
   */
  @ThreadSafe
  public abstract class BaseDseAuthenticator implements SyncAuthenticator {
  
    private static final String DSE_AUTHENTICATOR =
        "com.datastax.bdp.cassandra.auth.DseAuthenticator";
  
    private final String serverAuthenticator;
  
    protected BaseDseAuthenticator(@NonNull String serverAuthenticator) {
      this.serverAuthenticator = serverAuthenticator;
    }
  
    /**
     * Return a byte buffer containing the required SASL mechanism.
     *
     * <p>This should be one of:
     *
     * <ul>
     *   <li>PLAIN
     *   <li>GSSAPI
     * </ul>
     *
     * This must be either a {@linkplain ByteBuffer#asReadOnlyBuffer() read-only} buffer, or a new
     * instance every time.
     */
    @NonNull
    protected abstract ByteBuffer getMechanism();
  
    /**
     * Return a byte buffer containing the expected successful server challenge.
     *
     * <p>This should be one of:
     *
     * <ul>
     *   <li>PLAIN-START
     *   <li>GSSAPI-START
     * </ul>
     *
     * This must be either a {@linkplain ByteBuffer#asReadOnlyBuffer() read-only} buffer, or a new
     * instance every time.
     */
    @NonNull
    protected abstract ByteBuffer getInitialServerChallenge();
  
    @Nullable
    @Override
    public ByteBuffer initialResponseSync() {
      // DseAuthenticator communicates back the mechanism in response to server authenticate message.
      // older authenticators simply expect the auth response with credentials.
      if (isDseAuthenticator()) {
        return getMechanism();
      } else {
        return evaluateChallengeSync(getInitialServerChallenge());
      }
    }
  
    @Override
    public void onAuthenticationSuccessSync(@Nullable ByteBuffer token) {}
  
    private boolean isDseAuthenticator() {
      return serverAuthenticator.equals(DSE_AUTHENTICATOR);
    }
  }
  