设计模式说明
设计模式说明Produce by Shjy.Nicholas?????? E-Mail: shjy.nicholas@gmail.comVersion: 1.0??????????? ????????说明:本文是<<设计模式-- 可复用面向对象软件的基础>>,英文名称"Design Patterns -- Elements of Reusable Object-Oriented Software"一书的复习资料.原书的作者是: Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides.译者是: 李英军, 马晓星, 蔡敏, 刘建中.文中所表示的页码也是中文版的页码数.?一. OMT表示法的简单实例 类名 操作 数据 1. 类????
?? public class Name {??????????? // Name 为类名????? private String data ;????????? // data为数据????? public void operation() {}??????? // operation()为操作}?2.实例化 对象 ---> 类 ?? 在Java中,就是new操作,此时会使对象内部的数据分配存储空间.?3. 继承关系?? public class ParentClass {????? public void sayHello() {??????? System.out.println(“Hello in ParentClass”) ;}?? }??? public class SubClass extends ParentClass {????? public void sayHi() {??????? System.out.println(“Hi in SubClass”) ;????? }?????? public static void main(String [] args) {??????? SubClass sc = new SubClass() ;??????? sc.sayHello() ;??????? sc.sayHi() ;}?? }?/**?* 运行结果:?* Hello in ParentClass???? // 子类继承了父类中的方法SayHello()* Hi in SubClass?*/??4. 抽象类与具体类abstract class AbstractClass {?? public abstract void operation() ;}?class ConcreteSubClass extends AbstractClass {?? public void operation() {????? System.out.println("operation...") ;?? }}?5.混入类在java中不直接支持多继承,可以通过implements多个接口来实现.interface ExistingInterface {?? void existingOperation() ;}?interface Mixin {?? void mixinOperation() ;}?class AugmentedClass implements ExistingInterface, Mixin {?? public void existingOperation() {????? System.out.println("existingOperation()") ;?? }?? ?? public void mixinOperation() {????? System.out.println("mixinOperation()") ;?? }}??二. 委托class Rectangle {?? public int width ;?? public int height ;?? ?? public int area(){????? return width * height ;?? }}?class Window {?? Rectangle rectangle = new Rectangle() ;?? ?? public int area() {????? return rectangle.area() ;?? }}?三. Lexi说明.1. 设计中涉及到7种设计模式,分别是Abstract Factory, Composite, Strategy, Decorator, Bridge, Command, Iterator.?2. 设计问题:u????? 文档结构:Lexi的用户可以直接操纵行,列,图形,表等子结构.使用到的模式: 组合模式.u????? 格式化:将一个图元集合分解为若干行.格式化不同于表示,Lexi必须将文本分解成行,将行分解成列等操作,同时还要满足用户的高层次要求,如:指定边界宽度,缩进大小和表格形式,是否隔行显示以及其他可能的许多格式限制条件.使用的模式: 策略模式.u????? 修饰用户界面:支持两种修饰:n??????? 在文本编辑区域周围加边界以界定文本页.n??????? 加滚动条.???使用的模式: 装饰模式.u????? 支持多种视感标准:支持多种视感标准,以满足平台移植的要求.使用模式: 抽象工厂.u????? 支持多种窗口系统:解决移植中的窗口环境.使用模式: 桥接模式.u????? 用户操作: 通过文档的WYSIWYG(所见即所得)得到,并支持撤销和重做功能,以及命令历史记录.使用得模式: 命令模式.u????? 拼写检查和连字符: 1.访问以图元形式存在的,分散在文档结构中的信息.2.分析这些信息使用的模式:迭代器模式.四. 重要模式的说明:
1. Abstract Factory 抽象工厂模式???
???抽象工厂模式涉及到以下角色:u????? 抽象工厂角色: 担任这个角色的是工厂方法模式的核心,它是与应用系统的商业逻辑无关的.u????? 具体工厂角色: 这个角色直接在客户端的调用下创建产品的实例.u????? 抽象产品角色: 担任这个角色的类是工厂方法模式所创建的对象的父类,或它们共同拥有的接口.u????? 具体产品角色: 抽象工厂模式所创建的任何产品对象都是某一个具体产品类的实例.
在书P58页的结构图中,抽象工厂角色:AbstractFactory具体工厂角色:ConcreteFactory1, ConcreteFactory2抽象产品角色:AbstractProductA, AbstractProductB具体产品角色:ProductA1, ProductA2, ProductB1, ProductB2?2. Builder 生成器模式
Builder涉及到的角色: (括号内为所举例子中所对应的类名)u????? 抽象创造者(Builder)u????? 具体创造者(ConcreteBuilder)u????? 导演者(Director)u????? 产品(Product)
举例说明:abstract public class Builder {public abstract void buildPart1();public abstract void buildPart2();?public abstract Product retrieveResult();}?public class ConcreteBuilder extends Builder {private Product product = new Product() ;?public void buildPart1() {?? product.setPart1(“Part1 be build”) ;}?public void buildPart2() {?? product.setPart2(“Part2 be build”) ;}?public Product retrieveResult(){????? return product;}}?public class Director {private Builder builder;?public Director(Builder builder) {this.builder = builder;}?public Product construct()builder.buildPart1();builder.buildPart2();return builder.retrieveResult();}}?public class Product {?? private String part1 = null ;?? private String part2 = null ;?public Product() {}??? public void setPart1(String part1){????? this.part1 = part1 ;?? }??? public String getPart1() {????? return this.part1 ;?? }??? public void setPart2(String part2){????? this.part2 = part2 ;?? }??? public String getPart2() {????? return this.part2 ;?? }?? ?? public String toString(){????? System.out.println(“part1: ” + this.getPart1()) ;????? System.out.println(“part2: ” + this.getPart2()) ;?? }}?public class Client {private Director director = null ;?? private Builder builder = null ;?public void doBuild() {????? director = new Director(new ConcreteBuilder());????? System.out.println(director. construct()) ;}}??3. Composite合成模式
涉及到的角色:u????? 抽象构件(Component)u????? 树叶构件(Leaf)u????? 树枝构件(Conmposite)?举例:public interface Component {Composite getComposite();?void sampleOperation();}?public class Leaf implements Component {public Composite getComposite(){return null;}?public void sampleOperation(){System.out.println("leaf say hello") ;}}??import java.util.Vector;import java.util.Enumeration;?public class Composite implements Component{?? private Vector componentVector = new java.util.Vector();?public Composite getComposite(){return this;}?public void add(Component component){componentVector.addElement(component);}?public void remove(Component component){componentVector.removeElement(component);}?public Enumeration components(){return componentVector.elements();}??? public void sampleOperation(){Enumeration enumeration = components();while (enumeration.hasMoreElements()){((Component)enumeration.nextElement()).sampleOperation();}}}??4．Strategy策略模式
对应于P209的结构图,
public class Context{?? private Strategy strategy;??? public Strategy setStrategy(Strategy strategy) {????? this.strategy = strategy ;?? }?? public void contextInterface(){this.strategy.strategyInterface();}}??abstract public class Strategy{public abstract void algorithmInterface();}?public class ConcreteStrategyA extends Strategy{public void algorithmInterface(){System.out.println("A") ;}}?public class ConcreteStrategyB extends Strategy{public void algorithmInterface(){System.out.println("B") ;}}?public class ConcreteStrategyC extends Strategy{public void algorithmInterface(){System.out.println("C") ;}}??5.Decorator装饰模式
基于P116的结构图,有如下代码:
public interface Component{?? void operation();}?public class ConcreteComponent implements Component{??? public void operation(){????? // 给对象添加一些指责?? }}?public class Decorator implements Component{?? private Component component = null ;?? ?? public Decorator(Component component){????? this.component = component;?? }?public void operation(){????? component.operation();?? }}?public class ConcreteDecorator extends Decorator{??? public void operation(){????? super.operation();// 调用Component对象的operation方法,来给组件添加指责?? }}?6.Bridge桥接模式
基于P101的结构图:
abstract public class Abstraction{?? private Implementor imp;?? ?? public void operation(){????? imp.operationImp();?? }}?public class RefinedAbstraction extends Abstraction{?? public void operation() {????? super.operation() ;????? // 可以增加进一步的处理?? }}?abstract public class Implementor{?? public abstract void operationImp();}?public class ConcreteImplementorA extends Implementor{?? public void operationImp(){????? System.out.println("Do something in ConcreteImplementorA ...");?? }}?public class ConcreteImplementorB extends Implementor{?? public void operationImp() {????? System.out.println("Do something in ConcreteImplementorB ...");?? }}??7.Command 1 楼 shjy.nicholas 2007-08-22 这是我辛苦总结的，希望对大家有点用处。
