Java设计模式（七） 模板模式-使用钩子

1，模板类

package com.pattern.template;
 
public abstract class CaffeineBeverageWithHook {
 
	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");
	}
 
	boolean customerWantsCondiments(){
		return true;
	}
 
}

2，模板的子类实现类

package com.pattern.template;
 
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
 
public class CoffeeWithHook extends CaffeineBeverageWithHook{
 
	/**
	 * @see com.pattern.template.CaffeineBeverageWithHook#brew()
	 */
	@Override
	void brew() {
		System.out.println("Dripping Coffee through filter");
	}
 
	/**
	 * @see com.pattern.template.CaffeineBeverageWithHook#addCondiments()
	 */
	@Override
	void addCondiments() {
		System.out.println("Adding Sugar and Milk");
	}
 
	public boolean customerWantsCondiments(){
		String answer = getUserInput();
 
		if(answer.toLowerCase().startsWith("y")){
			return true;
		} else{
			return false;
		}
	}
 
	private String getUserInput(){
		String answer = null;
		System.out.println("Would you like milk and sugar with your coffee (y/n)?");
 
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
 
		try {
			answer = in.readLine();
		} catch (IOException e) {
			System.out.println("IO Exception!");
		}
 
		if(answer == null){
			return "no";
		}
		return answer;
	}
 
}

3，测试类

package com.pattern.template;
 
public class BeverageTestDrive {
 
	public static void main(String[] args) {
 
		CoffeeWithHook coffeeHook = new CoffeeWithHook();
		System.out.println("\nMaking tea...");
		coffeeHook.prepareRecipe();
	}
}

4，输出结果：

Making tea...

Boiling water

Dripping Coffee through filter

Pouring into cup

Would you like milk and sugar with your coffee (y/n)?

y

Adding Sugar and Milk