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