学习JavaScript设计模式之模板方法模式

/* 抽象父类：饮料 */
var Beverage = function(){};
// (1) 把水煮沸
Beverage.prototype.boilWater = function() {
  console.log("把水煮沸");
};
// (2) 沸水浸泡
Beverage.prototype.brew = function() {
  throw new Error("子类必须重写brew方法");
};
// (3) 倒进杯子
Beverage.prototype.pourInCup = function() {
  throw new Error("子类必须重写pourInCup方法");
};
// (4) 加调料
Beverage.prototype.addCondiments = function() {
  throw new Error("子类必须重写addCondiments方法");
};

/* 模板方法 */
Beverage.prototype.init = function() {
  this.boilWater();
  this.brew();
  this.pourInCup();
  this.addCondiments();
}

/* 实现子类 Coffee*/
var Coffee = function(){};
Coffee.prototype = new Beverage();
// 重写非公有方法
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("加牛奶");
};
var coffee = new Coffee();
coffee.init();

/* 添加钩子方法 */
Beverage.prototype.customerWantsCondiments = function() {
  return true;
};
Beverage.prototype.init = function() {
  this.boilWater();
  this.brew();
  this.pourInCup();
  if(this.customerWantsCondiments()) {
    this.addCondiments();
  }
}

/* 实现子类 Tea*/
var Tea = function(){};
Tea.prototype = new Beverage();
// 重写非公有方法
Tea.prototype.brew = function() {
  console.log("用沸水冲泡茶");
};
Tea.prototype.pourInCup = function() {
  console.log("把茶倒进杯子");
};
Tea.prototype.addCondiments = function() {
  console.log("加牛奶");
};
Tea.prototype.customerWantsCondiments = function() {
  return window.confirm("需要添加调料吗？");
};
var tea = new Tea();
tea.init();