Java设计模式（七） 模板模式

【模板模式】在一个方法中定义了一个算法的骨架，而将一些步骤延迟到子类中。模板方法使得子类可以在不改变算法结构的情况下，重新定义算法中的某些步骤。

1，定义模板类

package com.pattern.template;

public abstract class CaffeineBeverage {

	final void prepareRecipe(){
		boilWater();
		brew();
		pourInCup();
		addCondiments();
	}

	abstract void brew();
	abstract void addCondiments();

	void boilWater(){
		System.out.println("Boiling water");
	}

	void pourInCup(){
		System.out.println("Pouring into cup");
	}

}

2，定义模板的子类实现类

package com.pattern.template;

public class Coffee extends CaffeineBeverage{

	/**
	 * @see com.pattern.template.CaffeineBeverage#brew()
	 */
	@Override
	void brew() {
		System.out.println("Dripping Coffee through filter");
	}

	/**
	 * @see com.pattern.template.CaffeineBeverage#addCondiments()
	 */
	@Override
	void addCondiments() {
		System.out.println("Adding Sugar and Milk");
	}
}

package com.pattern.template;

public class Tea extends CaffeineBeverage{

	/**
	 * @see com.pattern.template.CaffeineBeverage#brew()
	 */
	@Override
	void brew() {
		System.out.println("Steeping the tea");
	}

	/**
	 * @see com.pattern.template.CaffeineBeverage#addCondiments()
	 */
	@Override
	void addCondiments() {
		System.out.println("Adding Lemon");
	}

}

3，测试类

package com.pattern.template;

public class BeverageTestDrive {

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

运行结果如下：

Boiling water

Dripping Coffee through filter

Pouring into cup

Adding Sugar and Milk

类图如下所示：