/*
 * 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.calcite.avatica.server;

import java.util.concurrent.Callable;

/**
 * A callback which the server can invoke to allow implementations to control additional logic
 * about whether or not a client from a specific host should be run.
 * <p>For example, complex logic could be supplied to control whether clientA from host1 is
 * permitted to execute queries. This logic is deferred upon the user to implement.
 */
public interface DoAsRemoteUserCallback {

  /**
   * Invokes the given <code>action</code> as the <code>remoteUserName</code>.
   *
   * @param remoteUserName The remote user making a request to the Avatica server.
   * @param remoteAddress The address the remote user is making the request from.
   * @param action The operation the Avatica server wants to run as <code>remoteUserName</code>.
   * @return The result from the Callable.
   */
  <T> T doAsRemoteUser(String remoteUserName, String remoteAddress, Callable<T> action)
      throws Exception;

}

// End DoAsRemoteUserCallback.java