text: /**
   * Copyright 2012 Google Inc. All Rights Reserved.
   *
   * 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.
   */
  
  /**
   * @author benvanik@google.com (Ben Vanik)
   */
  
  goog.provide('gf.sim.IEntityWatcher');
  
  
  
  /**
   * Entity watcher interface.
   * Entity watchers get notified when entities change in the simulation. They
   * must be registered with {@see gf.sim.Simulator#addWatcher}.
   *
   * @interface
   */
  gf.sim.IEntityWatcher = function() {};
  
  
  /**
   * Handles entities after they have been added to the simulation.
   * Note that the entity properties may not have been initialized yet.
   * @param {!gf.sim.Entity} entity Entity that was added.
   */
  gf.sim.IEntityWatcher.prototype.entityAdded;
  
  
  /**
   * Handles entities after they have been removed from the simulation.
   * @param {!gf.sim.Entity} entity Entity that was removed.
   */
  gf.sim.IEntityWatcher.prototype.entityRemoved;
  