《Java与模式》重点总结04.docx
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《Java与模式》重点总结04
八、代理（Proxy）模式
1、代理模式
（1）示例类图
（2）示例代码清单
/*
*创建日期2007-3-13
*
*TODO要更改此生成的文件的模板，请转至
*窗口－首选项－Java－代码样式－代码模板
*/
packagecom.langsin.proxy;
//抽象角色
abstractpublicclassSubject{
abstractpublicvoidrequest（）;
}
packagecom.langsin.proxy;
//真实角色：
实现了Subject的request（）方法
publicclassRealSubjectextendsSubject{
publicRealSubject（）{
}
publicvoidrequest（）{
System.out.println（"Fromrealsubject."）;
}
}
packagecom.langsin.proxy;
//代理角色
publicclassProxySubjectextendsSubject{
privateRealSubjectrealSubject;//以真实角色作为代理角色的属性
publicProxySubject（）{
}
publicvoidrequest（）//该方法封装了真实对象的request方法
{
preRequest（）;
if（realSubject==null）{
realSubject=newRealSubject（）;
}
realSubject.request（）;//此处执行真实对象的request方法
postRequest（）;
}
privatevoidpreRequest（）{
//somethingyouwanttodobeforerequesting
}
privatevoidpostRequest（）{
//somethingyouwanttodoafterrequesting
}
}
packagecom.langsin.proxy;
//客户端调用
publicclassClient{
publicstaticvoidmain（String[]args）{
Subjectsub=newProxySubject（）;
sub.request（）;
}
}
2、动态代理模式
（1）示例类图
（2）示例代码清单
packagecom.langsin.dynamicproxy;
//抽象角色（之前是抽象类，此处应改为接口）：
publicinterfaceSubject{
abstractpublicvoidrequest（）;
}
packagecom.langsin.dynamicproxy;
//具体角色
publicclassRealSubjectimplementsSubject{
publicRealSubject（）{
}
publicvoidrequest（）{
System.out.println（"Fromrealsubject."）;
}
}
packagecom.langsin.dynamicproxy;
importjava.lang.reflect.InvocationHandler;
importjava.lang.reflect.Method;
//代理处理器
/**
*该代理类的内部属性为Object类，实际使用时通过该类的构造函数DynamicSubject（Objectobj）对其赋值；
*此外，在该类还实现了invoke方法，该方法中的method.invoke（sub,args）;
*其实就是调用被代理对象的将要被执行的方法，方法参数sub是实际的被代理对象，args为执行被代理对象相应操作所需的参数。
*通过动态代理类，我们可以在调用之前或之后执行一些相关操作
*/
publicclassDynamicSubjectimplementsInvocationHandler{
privateObjectsub;
publicDynamicSubject（）{
}
publicDynamicSubject（Objectobj）{
sub=obj;
}
publicObjectinvoke（Objectproxy,Methodmethod,Object[]args）
throwsThrowable{
System.out.println（"beforecalling"+method）;
Objectobject=method.invoke（sub,args）;
System.out.println（"aftercalling"+method）;
returnobject;
}
}
packagecom.langsin.dynamicproxy;
importjava.lang.reflect.InvocationHandler;
importjava.lang.reflect.Proxy;
//客户端
publicclassClient{
staticpublicvoidmain（String[]args）throwsThrowable{
Subjectrs=newRealSubject（）;//在这里指定被代理类
InvocationHandlerds=newDynamicSubject（rs）;
Class
>cls=rs.getClass（）;
//以下是一次性生成代理
Subjectsubject=（Subject）Proxy.newProxyInstance（
cls.getClassLoader（）,cls.getInterfaces（）,ds）;
subject.request（）;
}
}
（3）其它示例类图
九、享元（Flyweight）模式
1、单纯享元模式
（1）示例类图
（2）示例代码清单
packagecom.javapatterns.flyweight.simple;
abstractpublicclassFlyweight{
abstractpublicvoidoperation（Stringstate）;
}
packagecom.javapatterns.flyweight.simple;
publicclassConcreteFlyweightextendsFlyweight{
privateCharacterintrinsicState=null;
publicConcreteFlyweight（Characterstate）{
this.intrinsicState=state;
}
publicvoidoperation（Stringstate）{
System.out.print（"\nIntrinsicState="+intrinsicState
+",ExtrinsicState="+state）;
}
}
packagecom.javapatterns.flyweight.simple;
importjava.util.Map;
importjava.util.HashMap;
importjava.util.Iterator;
publicclassFlyweightFactory{
privateHashMapflies=newHashMap（）;
/**
*@linkaggregation
*@directed
*@clientRoleFlyweights
*/
privateFlyweightlnkFlyweight;
publicFlyweightFactory（）{
}
publicsynchronizedFlyweightfactory（Characterstate）{
if（flies.containsKey（state））{
return（Flyweight）flies.get（state）;
}else{
Flyweightfly=newConcreteFlyweight（state）;
flies.put（state,fly）;
returnfly;
}
}
publicvoidcheckFlyweight（）{
Flyweightfly;
inti=0;
System.out.println（"\n==========checkFlyweight（）============="）;
for（Iteratorit=flies.entrySet（）.iterator（）;it.hasNext（）;）{
Map.Entrye=（Map.Entry）it.next（）;
System.out.println（"Item"+（++i）+":
"+e.getKey（））;
}
System.out.println（"==========checkFlyweight（）============="）;
}
}
packagecom.javapatterns.flyweight.simple;
publicclassClient{
privatestaticFlyweightFactoryfactory;
staticpublicvoidmain（String[]args）{
factory=newFlyweightFactory（）;
Flyweightfly=factory.factory（newCharacter（'a'））;
fly.operation（"FirstCall"）;
fly=factory.factory（newCharacter（'b'））;
fly.operation（"SecondCall"）;
fly=factory.factory（newCharacter（'a'））;
fly.operation（"ThirdCall"）;
//intrinsicFlyweight
factory.checkFlyweight（）;
}
}
输出结果：
IntrinsicState=a,ExtrinsicState=FirstCall
IntrinsicState=b,ExtrinsicState=SecondCall
IntrinsicState=a,ExtrinsicState=ThirdCall
==========checkFlyweight（）=============
Item1:
b
Item2:
a
==========checkFlyweight（）=============
2、复合享元模式
（1）示例类图
（2）示例代码清单
packageposite;
abstractpublicclassFlyweight{
abstractpublicvoidoperation（Stringstate）;
}
packageposite;
publicclassConcreteFlyweightextendsFlyweight{
privateCharacterintrinsicState=null;
publicConcreteFlyweight（Characterstate）{
this.intrinsicState=state;
}
publicvoidoperation（Stringstate）{
System.out.print（"\nInternalState="+intrinsicState
+"ExtrinsicState="+state）;
}
}
packageposite;
importjava.util.Map;
importjava.util.HashMap;
importjava.util.Iterator;
publicclassConcreteCompositeFlyweightextendsFlyweight{
privateHashMapflies=newHashMap（10）;
/**
*@linkaggregation
*@directed
*@clientRoleComposite
*/
privateFlyweightflyweight;
publicConcreteCompositeFlyweight（）{
}
publicvoidadd（Characterkey,Flyweightfly）{
flies.put（key,fly）;
}
publicvoidoperation（StringextrinsicState）{
Flyweightfly=null;
for（Iteratorit=flies.entrySet（）.iterator（）;it.hasNext（）;）{
Map.Entrye=（Map.Entry）it.next（）;
fly=（Flyweight）e.getValue（）;
fly.operation（extrinsicState）;
}
}
}
packageposite;
importjava.util.Map;
importjava.util.HashMap;
importjava.util.Iterator;
publicclassFlyweightFactory{
privateHashMapflies=newHashMap（）;
/**
*@linkaggregation
*@directed
*@clientRoleFlyweights
*/
privateFlyweightlnkFlyweight;
publicFlyweightFactory（）{
}
publicFlyweightfactory（StringcompositeState）{
ConcreteCompositeFlyweightcompositeFly=newConcreteCompositeFlyweight（）;
intlength=compositeState.length（）;
Characterstate=null;
for（inti=0;istate=newCharacter（compositeState.charAt（i））;
System.out.println（"factory（"+state+"）"）;
compositeFly.add（state,this.factory（state））;
}
returncompositeFly;
}
publicFlyweightfactory（Characterstate）{
if（flies.containsKey（state））{
return（Flyweight）flies.get（state）;
}else{
Flyweightfly=newConcreteFlyweight（state）;
flies.put（state,fly）;
returnfly;
}
}
publicvoidcheckFlyweight（）{
Flyweightfly;
inti=0;
System.out.println（"\n==========checkFlyweight（）============="）;
for（Iteratorit=flies.entrySet（）.iterator（）;it.hasNext（）;）{
Map.Entrye=（Map.Entry）it.next（）;
System.out.println（"Item"+（++i）+":
"+e.getKey（））;
}
System.out.println（"\n==========checkFlyweight（）============="）;
}
}
packageposite;
publicclassClient{
privatestaticFlyweightFactoryfactory;
publicstaticvoidmain（String[]args）{
factory=newFlyweightFactory（）;
Flyweightfly;
/*
*fly=factory.factory（newCharacter（'a'））;fly.operation（）;
*
*fly=factory.factory（newCharacter（'b'））;fly.operation（）;
*
*fly=factory.factory（newCharacter（'a'））;fly.operation（）;
*/
fly=factory.factory（"abcb"）;
fly.operation（"CompositeCall"）;
//intrinsicFlyweight
factory.checkFlyweight（）;
}
}
十、门面（Facade）模式
（1）示例类图
（2）示例代码清单
packagecom.javapatterns.facade.securityfacade;
publicclassSecurityFacade{
privateCameracamera1,camera2;
privateLightlight1,light2,light3;
privateSensorsensor;
privateAlarmalarm;
publicSecurityFacade（）{
camera1=newCamera（）;
camera2=newCamera（）;
light1=newLight（）;
light2=newLight（）;
light3=newLight（）;
sensor=newSensor（）;
alarm=newAlarm（）;
}
publicvoidactivate（）{
camera1.turnOn（）;
camera2.turnOn（）;
light1.turnOn（）;
light2.turnOn（）;
light3.turnOn（）;
sensor.activate（）;
alarm.activate（）;
}
publicvoiddeactivate（）{
camera1.turnOff（）;
camera2.turnOff（）;
light1.turnOff（）;
light2.turnOff（）;
light3.turnOff（）;
sensor.deactivate（）;
alarm.deactivate（）;
}
}
packagecom.javapatterns.facade.securityfacade;
publicclassAlarm{
publicvoidactivate（）{
System.out.println（"Activatingthealarm."）;
}
publicvoiddeactivate（）{
System.out.println（"Deactivatingthealarm."）;
}
publicvoidring（）{
System.out.println（"Ringthealarm."）;
}
publicvoidstopRing（）{
System.out.println（"Stopthealarm."）;
}
}
packagecom.javapatterns.facade.securityfacade;
publicclassCamera{
publicvoidturnOn（）{
System.out.println（"Turningonthecamera."）;
}
publicvoidturnOff（）{
System.out.println（"Turningoffthecamera."）;
}
publicvoidrotate（intdegrees）{
System.out.println（"Rotatingthecameraby"+degrees+"degrees."）;
}
}
packagecom.javapatterns.facade.securityfacade;
publicclassLight{
publicvoidturnOn（）{
System.
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