/*
* Copyright 2015 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.
*/
package com.google.android.agera;
/**
* Passes on updates from an {@link Updatable#update} call to any {@link Updatable} added using
* {@link Observable#addUpdatable}. It should be possible to call {@link UpdateDispatcher#update}
* from any thread.
*
* <p>This interface should typically not be implemented by client code; the standard
* implementations obtainable from {@link Observables#updateDispatcher} help implement
* {@link Observable}s adhering to the contract.
*
* Agera 中抽象出来的 观察者调度者 接口
* 由于自身 继承了 被观察者（ Observable ）接口 和 观察者（ Updatable ）接口
* 所以自身就能够拥有两者的功能
* 使用场景有：
* 一个 Activity 继承了 观察者（ Updatable ）接口
* 一个 BroadcastReceiver 继承了 被观察者（ Observable ）接口
* 这个 BroadcastReceiver 持有一个 UpdateDispatcher 的引用
*
* 这个 UpdateDispatcher 通过 观察者（ Updatable ）接口的功能 去添加 一个 观察者（ Updatable ） -> Activity
*
* 然后：
* Activity 发送广播
* BroadcastReceiver 的 onReceive(...) 接受到该广播
* 调用 UpdateDispatcher 的通过自身的被观察者功能去 调用 已经添加的 观察者（ Updatable ）的 update
*
* 这个接口，一般不能不能由开发者去实现其功能，而是通过 Observables.updateDispatcher(...) 获取一个对象
*/
public interface UpdateDispatcher extends Observable, Updatable {}