/**
 * Copyright 2009 Google Inc.
 *
 * 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
 *
 *      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.waveprotocol.wave.model.conversation;

import org.waveprotocol.wave.model.wave.SourcesEvents;

/**
 * Extends {@link ManifestBlip} to provide events that can be listened to.
 *
 * @author zdwang@google.com (David Wang)
 */
interface ObservableManifestBlip extends ManifestBlip,
    SourcesEvents<ObservableManifestBlip.Listener>, HasId {
  /**
   * Receives events on a {@link ManifestBlip}.
   */
  public interface Listener {
    /**
     * Called when a reply is added to the blip.
     */
    void onReplyAdded(ObservableManifestThread thread);

    /**
     * Called when a reply is removed from the blip.
     */
    void onReplyRemoved(ObservableManifestThread thread);
  }

  /**
   * Removes all listeners from this blip.
   */
  void detachListeners();

  // Covariant specialisations.

  @Override
  ObservableManifestThread appendReply(String id, boolean inline);

  @Override
  ObservableManifestThread insertReply(int index, String id, boolean inline);

  @Override
  ObservableManifestThread getReply(int index);

  @Override
  Iterable<? extends ObservableManifestThread> getReplies();
}