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.session.throttling;
  
  import com.datastax.oss.driver.api.core.RequestThrottlingException;
  import edu.umd.cs.findbugs.annotations.NonNull;
  
  /**
   * A request that may be subjected to throttling by a {@link
   * com.datastax.oss.driver.api.core.session.throttling.RequestThrottler}.
   */
  public interface Throttled {
  
    /**
     * Invoked by the throttler to indicate that the request can now start. The request must wait for
     * this call until it does any "actual" work (typically, writing to a connection).
     *
     * @param wasDelayed indicates whether the throttler delayed at all; this is so that requests
     *     don't have to rely on measuring time to determine it (this is useful for metrics).
     */
    void onThrottleReady(boolean wasDelayed);
  
    /**
     * Invoked by the throttler to indicate that the request cannot be fulfilled. Typically, this
     * means we've reached maximum capacity, and the request can't even be enqueued. This error must
     * be rethrown to the client.
     *
     * @param error the error that the request should be completed (exceptionally) with.
     */
    void onThrottleFailure(@NonNull RequestThrottlingException error);
  }
  