设计模式11-模板方法模式

package DesignPattern;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class TemplateMethodPattern {
    //模板方法模式
    //要点在于共享算法流程，这类似于工厂方法模式
    //不同之处在于：
    // 工厂方法模式关注产品的最初的复杂创建，并提供给子类自定以创建的接口
    // 模板方法模式关注产品加工流程的方法，提供给子类自定义创建接口
    public static abstract class CaffeineBeverageWithHook{
        final void prepareRecipe(){
            boilWater();
            brew();
            pourInCup();
            if(customerWantsCondiments()){
                addCondiments();
            }
        }
        abstract void brew();
        abstract void addCondiments();
        void boilWater(){
            System.out.println("Boiling water");
        }
        void pourInCup(){
            System.out.println("Pouring into cup");
        }
        //Hook
        boolean customerWantsCondiments(){
            return true;
        }
    }

    public static class CoffeeWithHook extends CaffeineBeverageWithHook{
        @Override
        public void brew(){
            System.out.println("Drpping Coffee through filter");
        }

        @Override
        void addCondiments() {
            System.out.println("Adding Sugar and milk");
        }

        @Override
        boolean customerWantsCondiments() {
            String answer = getUserInput();
            if (answer.startsWith("y"))
                return true;
            return false;
        }

        private String getUserInput(){
            String answer=null;
            BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
            System.out.println("would you want condiments?");
            try {
                answer=in.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            if(answer==null)answer="no";
            return answer;
        }
    }

    public static void main(String[] args) {
        CoffeeWithHook cwh = new CoffeeWithHook();
        cwh.prepareRecipe();
    }

}