【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: