content: /*
   * Copyright 2014-2025 Real Logic Limited.
   *
   * Licensed 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
   *
   * https://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 io.aeron.driver;
  
  import org.agrona.concurrent.status.ReadablePosition;
  
  /**
   * Stream source that can be observed by subscribers which identify themselves the position they have read up to.
   */
  public interface Subscribable
  {
      /**
       * Registration ID that is in use by the subscribable.
       *
       * @return registration ID for subscribable.
       */
      long subscribableRegistrationId();
  
      /**
       * Add a subscriber and its position used for tracking consumption.
       *
       * @param subscriptionLink   for identifying the subscriber.
       * @param subscriberPosition for tracking the subscriber.
       * @param nowNs              for the current time.
       */
      void addSubscriber(SubscriptionLink subscriptionLink, ReadablePosition subscriberPosition, long nowNs);
  
      /**
       * Remove a subscriber and its position used for tracking consumption.
       * <p>
       * <b>Note:</b> The {@link Subscribable} is responsible for calling {@link ReadablePosition#close()} on
       * removed positions.
       *
       * @param subscriptionLink   for identifying the subscriber.
       * @param subscriberPosition for tracking the subscriber.
       */
      void removeSubscriber(SubscriptionLink subscriptionLink, ReadablePosition subscriberPosition);
  }
  