103 lines
2.0 KiB
Markdown
103 lines
2.0 KiB
Markdown
# 模板方法（Template Method）
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## Intent
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定义算法框架，并将一些步骤的实现延迟到子类。
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通过模板方法，子类可以重新定义算法的某些步骤，而不用改变算法的结构。
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## Class Diagram
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\
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## Implementation
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冲咖啡和冲茶都有类似的流程，但是某些步骤会有点不一样，要求复用那些相同步骤的代码。
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\
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```java
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public abstract class CaffeineBeverage {
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final void prepareRecipe() {
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boilWater();
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brew();
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pourInCup();
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addCondiments();
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}
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abstract void brew();
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abstract void addCondiments();
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void boilWater() {
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System.out.println("boilWater");
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}
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void pourInCup() {
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System.out.println("pourInCup");
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}
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}
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```
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```java
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public class Coffee extends CaffeineBeverage {
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@Override
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void brew() {
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System.out.println("Coffee.brew");
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}
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@Override
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void addCondiments() {
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System.out.println("Coffee.addCondiments");
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}
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}
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```
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```java
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public class Tea extends CaffeineBeverage {
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@Override
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void brew() {
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System.out.println("Tea.brew");
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}
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@Override
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void addCondiments() {
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System.out.println("Tea.addCondiments");
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}
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}
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```
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```java
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public class Client {
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public static void main(String[] args) {
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CaffeineBeverage caffeineBeverage = new Coffee();
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caffeineBeverage.prepareRecipe();
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System.out.println("-----------");
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caffeineBeverage = new Tea();
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caffeineBeverage.prepareRecipe();
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}
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}
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```
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```html
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boilWater
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Coffee.brew
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pourInCup
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Coffee.addCondiments
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-----------
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boilWater
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Tea.brew
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pourInCup
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Tea.addCondiments
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```
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## JDK
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* java.util.Collections#sort()
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* java.io.InputStream#skip()
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* java.io.InputStream#read()
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* java.util.AbstractList#indexOf()
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