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.celeborn.common.network.server;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.celeborn.common.network.client.RpcResponseCallback;
  import org.apache.celeborn.common.network.client.TransportClient;
  import org.apache.celeborn.common.network.protocol.RequestMessage;
  
  /**
   * RPC Handler which performs authentication, and when it's successful, delegates further calls to
   * another RPC handler. The authentication handshake itself should be implemented by subclasses.
   */
  public abstract class AbstractAuthRpcHandler extends BaseMessageHandler {
    /** RpcHandler we will delegate to for authenticated connections. */
    private static final Logger LOG = LoggerFactory.getLogger(AbstractAuthRpcHandler.class);
  
    protected final BaseMessageHandler delegate;
  
    private boolean isAuthenticated;
  
    protected AbstractAuthRpcHandler(BaseMessageHandler delegate) {
      this.delegate = delegate;
    }
  
    /**
     * Responds to an authentication challenge.
     *
     * @return Whether the client is authenticated.
     */
    protected abstract boolean doAuthChallenge(
        TransportClient client, RequestMessage message, RpcResponseCallback callback);
  
    @Override
    public final void receive(
        TransportClient client, RequestMessage message, RpcResponseCallback callback) {
      if (isAuthenticated) {
        LOG.trace("Already authenticated. Delegating {}", client.getClientId());
        delegate.receive(client, message, callback);
      } else {
        isAuthenticated = doAuthChallenge(client, message, callback);
      }
    }
  
    @Override
    public final void receive(TransportClient client, RequestMessage message) {
      if (isAuthenticated) {
        delegate.receive(client, message);
      } else {
        throw new SecurityException("Unauthenticated call to receive().");
      }
    }
  
    @Override
    public void channelActive(TransportClient client) {
      delegate.channelActive(client);
    }
  
    @Override
    public void channelInactive(TransportClient client) {
      delegate.channelInactive(client);
    }
  
    @Override
    public void exceptionCaught(Throwable cause, TransportClient client) {
      delegate.exceptionCaught(cause, client);
    }
  
    public boolean isAuthenticated() {
      return isAuthenticated;
    }
  }
  