茂名市城市建设档案馆网站,有谁做分销网站,中山建设监理有限公司 网站,网上竞价投标流程文章目录一、引入二、代理模式#xff0c;Prototype Pattern2.1 Intent 意图2.2 Applicability 适用性2.3 类图2.4 应用实例#xff1a;使用下划线或消息框展示字符串2.4 应用实例#xff1a;JDK java.lang.Object java.lang.Cloneable一、引入
二、代理模式#xff0c;Pr…
文章目录一、引入二、代理模式Prototype Pattern2.1 Intent 意图2.2 Applicability 适用性2.3 类图2.4 应用实例使用下划线或消息框展示字符串2.4 应用实例JDK java.lang.Object java.lang.Cloneable一、引入
二、代理模式Prototype Pattern
代理模式实现了一个原型接口用于创建当前对象的克隆。
2.1 Intent 意图
Specify the kinds of objects to create using a prototypical instance, and create new objects by copying this prototype. 使用原型实例指定要创建的对象类型并通过克隆此原型来创建新对象
2.2 Applicability 适用性
When a system should be independent of how its products are created, composed, and represented. 当一个系统应该独立于它的产品创建构成和表示时When the classes to instantiate are specified at run-time, for example, by dynamic loading. 当要实例化的类是在运行时刻指定时例如通过动态装载.To avoid building a class hierarchy of factories that parallels the class hierarchy of products. 为了避免创建一个与产品类层次平行的工厂类层次时. (工厂模式介绍)When instances of a class can have one of only a few different combinations of state. 当一个类的实例只能有几个不同状态组合中的一种时.
2.3 类图 Prototype: Declares an interface for cloning itself. 声明一个用于克隆自身的接口ConcretePrototype: Implements an operation for cloning itself. 实现一个克隆自身的操作
2.4 应用实例使用下划线或消息框展示字符串
To show a string with underline or message box:
Conventionally, we have to design three different classes to show a string with underline or message boxHowever, we will design too many classes to show different underline or message box styles Prototype
public interface Product extends Cloneable {public abstract void use(String s);public abstract Product createClone();
}public class MessageBox implements Product {private char decochar;public MessageBox(char decochar) {this.decochar decochar;}public void use(String s) {int length s.getBytes().length;for (int i 0; i length 4; i) {System.out.print(decochar);}System.out.println();System.out.println(decochar s decochar);for (int i 0; i length 4; i) {System.out.print(decochar);}System.out.println();}public Product clone() {Product p null;try {p (Product) super.clone();} catch (CloneNotSupportedException e) {e.printStackTrace();}return p;}
}public class UnderlinePen implements Product {private char ulchar;public UnderlinePen(char ulchar) {this.ulchar ulchar;}public void use(String s) {int length s.getBytes().length;System.out.println(\ s \);System.out.print( );for (int i 0; i length; i) {System.out.print(ulchar);}System.out.println();}public Product clone() {Product p null;try {p (Product) super.clone();} catch (CloneNotSupportedException e) {e.printStackTrace();}return p;}
}Manager
public class Manager {private HashMap showcase new HashMapString, Product();public void register(String name, Product proto) {showcase.put(name, proto);}public Product create(String protoname) {Product p (Product) showcase.get(protoname);return p.clone();}
}ClientDemo
public class Main {public static void main(String[] args) {// 准备Manager manager new Manager();UnderlinePen upen new UnderlinePen(~);MessageBox mbox new MessageBox(*);MessageBox sbox new MessageBox(/);manager.register(strong message, upen);manager.register(warning box, mbox);manager.register(slash box, sbox);// 生成Product p1 manager.create(strong message);p1.use(Hello, world.);Product p2 manager.create(warning box);p2.use(Hello, world.);Product p3 manager.create(slash box);p3.use(Hello, world.);}
}2.4 应用实例JDK java.lang.Object java.lang.Cloneable
java.lang.Object
