/*
 * The MIT License
 * Copyright © 2014-2021 Ilkka Seppälä
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package com.iluwatar.reactor.framework;

import java.nio.channels.SelectionKey;

/**
 * Represents the event dispatching strategy. When {@link NioReactor} senses any event on the
 * registered {@link AbstractNioChannel}s then it de-multiplexes the event type, read or write or
 * connect, and then calls the {@link Dispatcher} to dispatch the read events. This decouples the
 * I/O processing from application specific processing. <br> Dispatcher should call the {@link
 * ChannelHandler} associated with the channel on which event occurred.
 *
 * <p>The application can customize the way in which event is dispatched such as using the reactor
 * thread to dispatch event to channels or use a worker pool to do the non I/O processing.
 *
 * @see SameThreadDispatcher
 * @see ThreadPoolDispatcher
 */
public interface Dispatcher {
  /**
   * This hook method is called when read event occurs on particular channel. The data read is
   * provided in <code>readObject</code>. The implementation should dispatch this read event to the
   * associated {@link ChannelHandler} of <code>channel</code>.
   *
   * <p>The type of <code>readObject</code> depends on the channel on which data was received.
   *
   * @param channel    on which read event occurred
   * @param readObject object read by channel
   * @param key        on which event occurred
   */
  void onChannelReadEvent(AbstractNioChannel channel, Object readObject, SelectionKey key);

  /**
   * Stops dispatching events and cleans up any acquired resources such as threads.
   *
   * @throws InterruptedException if interrupted while stopping dispatcher.
   */
  void stop() throws InterruptedException;
}
