/**
 * 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 Manifest} to provide events that can be listened to.
 *
 * @author anorth@google.com (Alex North)
 */
interface ObservableManifest extends Manifest, SourcesEvents<ObservableManifest.Listener> {
  /**
   * Receives events on a {@link Manifest}.
   */
  interface Listener {
    /**
     * Notifies this listener that the manifest anchor has changed.
     *
     * @param oldAnchor the old anchor values
     * @param newAnchor the new anchor values
     */
    void onAnchorChanged(AnchorData oldAnchor, AnchorData newAnchor);
  }

  // Covariant specialisations.

  @Override
  ObservableManifestThread getRootThread();
}
