function Beverage() {}

Beverage.prototype.boilWater = function() {

	console.log("把水煮沸");

}

Beverage.prototype.brew = function() {

	throw new Error('子类必须重写brew方法');

}

Beverage.prototype.pourInCup = function() {

	throw new Error('子类必须重写pourInCup方法');

}

Beverage.prototype.addCondiments = function() {

	throw new Error('子类必须重写addCondiments方法');

}

Beverage.prototype.init = function() {

	this.boilWater();

	this.brew();

	this.pourInCup();

	this.addCondiments();

}

function Coffee() {}

Coffee.prototype = new Beverage();

Coffee.prototype.brew = function() {

	console.log("用沸水冲泡咖啡");

}

Coffee.prototype.pourInCup = function() {

	console.log("把咖啡倒进杯子");

}

Coffee.prototype.addCondiments = function() {

	console.log("加糖和牛奶");

}

var coffee = new Coffee();

// coffee的原型Coffee没有init方法,

// 顺着原型链委托给父类的Beverage原型上的init方法

coffee.init();

console.log("-------------------------");

function Tea() {}

Tea.prototype = new Beverage();

Tea.prototype.brew = function() {

	console.log("用沸水浸泡茶叶");

}

Tea.prototype.pourInCup = function() {

	console.log("把茶水倒进杯子");

}

Tea.prototype.addCondiments = function() {

	console.log("加柠檬");

}

var tea = new Tea();

tea.init();