06、Caché 设计模式 - 原型模式

定义

用原型实例指定创建对象的种类，并且通过拷贝这些原型创建新的对象。

原型模式其实就是从一个对象再创建另外一个可定制的对象，而且不需要知道任何创建的细节。

使用场景

使用原形模式可以解决复杂对象构建资源消耗的问题。也可以用来只读保护。注意其java里继承Cloneable接口。C#继承ICloneable接口。Caché 直接使用%ConstructClone()方法，克隆时不会走构造函数。

优点

一般在初始化的信息不发生变的情况下，克隆是最好的办法，这即隐藏了对象创建的细节，又对性能是大大的提高。

不用重新初始化对象，而是动态地获得对象运行时的状态。

结构图

描述

要求有一个简历类，必须要有姓名，可以设置性别和年龄，可以设置工作经历。最终需要三分简历。

示例

简历类

Class PHA.YX.Design.Prototype.Resume Extends %RegisteredObject
{

Property name As %String [ Private ];

Property sex As %String [ Private ];

Property age As %String [ Private ];

Property timeArea As %String [ Private ];

Property company As %String [ Private ];
Method %OnNew(name As %String) As %Status [ Private, ServerOnly = 1 ]
{
	s $this.name = name
	Quit $$$OK
}

Method SetPersonalInfo(sex As %String, age As %String)
{
	s $this.sex=sex
	s $this.age=age
}

Method SetWorkExperience(timeArea As %String, company As %String)
{
	s $this.timeArea=timeArea
	s $this.company=company
}

Method Display()
{
	w ..name _ " " _ ..sex _ " " _ ..age,!
	w "工作经历：" _ ..timeArea _ " " _ ..company,!
}

}

初级写法

/// dclass(PHA.YX.Design.Program).PrototypeExamplePrimary() 
ClassMethod PrototypeExamplePrimary()
{
	s mResumeA =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeA.SetPersonalInfo("男","30")
	d mResumeA.SetWorkExperience("2015-2020","XX公司")
	
	s mResumeB =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeB.SetPersonalInfo("男","30")
	d mResumeB.SetWorkExperience("2015-2020","XX公司")
	
	s mResumeC =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeC.SetPersonalInfo("男","30")
	d mResumeC.SetWorkExperience("2015-2020","XX公司")
	
	d mResumeA.Display()
	d mResumeB.Display()
	d mResumeC.Display()
}

DHC-APP>dclass(PHA.YX.Design.Program).PrototypeExamplePrimary()
姚鑫 男 30
工作经历：2015-2020 XX公司
姚鑫 男 30
工作经历：2015-2020 XX公司
姚鑫 男 30
工作经历：2015-2020 XX公司
 

缺点

三分简历需要实例化三次，如果需要一百份，就需要实例化一百次，徒增内存。

中级写法

/// dclass(PHA.YX.Design.Program).PrototypeExampleIntermediate() 
ClassMethod PrototypeExampleIntermediate()
{
	s mResumeA =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeA.SetPersonalInfo("男","30")
	d mResumeA.SetWorkExperience("2015-2020","XX公司")
	
	# dim mResumeB as PHA.YX.Design.Prototype.Resume
	s mResumeB = mResumeA
	
	# dim mResumeC as PHA.YX.Design.Prototype.Resume
	s mResumeC = mResumeA
	
	d mResumeA.Display()
	d mResumeB.Display()
	d mResumeC.Display()
}

DHC-APP>dclass(PHA.YX.Design.Program).PrototypeExampleIntermediate()
姚鑫 男 30
工作经历：2015-2020 XX公司
姚鑫 男 30
工作经历：2015-2020 XX公司
姚鑫 男 30
工作经历：2015-2020 XX公司

缺点

引用传值，改动其中一处其他复制实例一起改动。把mResumeB设置一下年龄，mResumeC设置一下公司。如下：

/// dclass(PHA.YX.Design.Program).PrototypeExampleIntermediate() 
ClassMethod PrototypeExampleIntermediate()
{
	s mResumeA =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeA.SetPersonalInfo("男","30")
	d mResumeA.SetWorkExperience("2015-2020","XX公司")
	
	# dim mResumeB as PHA.YX.Design.Prototype.Resume
	s mResumeB = mResumeA
	d mResumeB.SetPersonalInfo("男","31")
	
	# dim mResumeC as PHA.YX.Design.Prototype.Resume
	s mResumeC = mResumeA
	d mResumeC.SetWorkExperience("2017-2020","SS公司")
	d mResumeA.Display()
	d mResumeB.Display()
	d mResumeC.Display()
}

运行结果

DHC-APP>dclass(PHA.YX.Design.Program).PrototypeExampleIntermediate()
姚鑫 男 31
工作经历：2017-2020 SS公司
姚鑫 男 31
工作经历：2017-2020 SS公司
姚鑫 男 31
工作经历：2017-2020 SS公司

高级写法 (浅复制)

使用.%ConstructClone()方法复制

/// dclass(PHA.YX.Design.Program).PrototypeExampleSenior() 
ClassMethod PrototypeExampleSenior()
{
	s mResumeA =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeA.SetPersonalInfo("男","30")
	d mResumeA.SetWorkExperience("2015-2020","XX公司")
	
	# dim mResumeB as PHA.YX.Design.Prototype.Resume
	s mResumeB = mResumeA.%ConstructClone()
	d mResumeB.SetPersonalInfo("男","31")
	
	# dim mResumeC as PHA.YX.Design.Prototype.Resume
	s mResumeC =mResumeA.%ConstructClone()
	d mResumeC.SetWorkExperience("2017-2020","SS公司")
	
	d mResumeA.Display()
	d mResumeB.Display()
	d mResumeC.Display()
}

DHC-APP> dclass(PHA.YX.Design.Program).PrototypeExampleSenior()
姚鑫 男 30
工作经历：2015-2020 XX公司
姚鑫 男 31
工作经历：2015-2020 XX公司
姚鑫 男 30
工作经历：2017-2020 SS公司

浅复制

如果字段是值类型的，则对该字段执行逐位复制，如果字段是引用类型，则复制引用但不复制引用的对象，因此原始对象及其副本引用统一对象。如下增加一个工作经验类的引用字段：

增加一个WorkExperience类

Class PHA.YX.Design.Prototype.WorkExperience Extends %RegisteredObject
{

Property workDate As %String [ Private ];

Method workDateGet() As %String [ ServerOnly = 1 ]
{
	Quit i%workDate
}

Method workDateSet(Arg As %String) As %Status [ ServerOnly = 1 ]
{
	s i%workDate = Arg
	Quit $$$OK
}

Property company As %String [ Private ];

Method companyGet() As %String [ ServerOnly = 1 ]
{
	Quit i%company
}

Method companySet(Arg As %String) As %Status [ ServerOnly = 1 ]
{
	s i%company = Arg
	Quit $$$OK
}

}

PHA.YX.Design.Prototype.Resume 增加一个work字段引用WorkExperience

Property work As WorkExperience [ Private ];

并且在构造方法初始化它

Method %OnNew(name As %String) As %Status [ Private, ServerOnly = 1 ]
{
	s $this.name = name
	s ..work =class(WorkExperience).%New()
	Quit $$$OK
}

给对象添加WorkExperience数据方法

Method CloneWorkExperience()
{
	s ..work = ..work.%ConstructClone()
}

输出也修改一下

Method Display()
{
	w ..name _ " " _ ..sex _ " " _ ..age,!
	w "工作经历：" _ ..timeArea _ " " _ ..company,!
	w "工作经历Object：" _ ..work.workDateGet() _ " " _ ..work.companyGet(),!
}

/// dclass(PHA.YX.Design.Program).PrototypeExampleShallow() 
ClassMethod PrototypeExampleShallow()
{
	s mResumeA =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeA.SetPersonalInfo("男","30")
	d mResumeA.SetWorkExperience("2015-2020","XX公司")
	d mResumeA.SetWorkExperienceObject("2010-2011","腾讯")
	
	# dim mResumeB as PHA.YX.Design.Prototype.Resume
	s mResumeB = mResumeA.%ConstructClone()
	d mResumeB.SetPersonalInfo("男","31")
	d mResumeB.SetWorkExperienceObject("2011-2012","阿里")
	
	# dim mResumeC as PHA.YX.Design.Prototype.Resume
	s mResumeC =mResumeA.%ConstructClone()
	d mResumeC.SetWorkExperience("2017-2020","SS公司")
	d mResumeC.SetWorkExperienceObject("2012-2013","百度")
	
	d mResumeA.Display()
	d mResumeB.Display()
	d mResumeC.Display()
}

DHC-APP> dclass(PHA.YX.Design.Program).PrototypeExampleShallow()
姚鑫 男 30
工作经历：2015-2020 XX公司
工作经历Object：2012-2013 百度
姚鑫 男 31
工作经历：2015-2020 XX公司
工作经历Object：2012-2013 百度
姚鑫 男 30
工作经历：2017-2020 SS公司
工作经历Object：2012-2013 百度

结果发现。引用的字段并没有重新复制。

深复制

我们在PHA.YX.Design.Prototype.Resume里给work属性，增加一个克隆方法。

Method CloneWorkExperience()
{
	s ..work = ..work.%ConstructClone()
}

/// dclass(PHA.YX.Design.Program).PrototypeExampleDeep() 
ClassMethod PrototypeExampleDeep()
{
	s mResumeA =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeA.SetPersonalInfo("男","30")
	d mResumeA.SetWorkExperience("2015-2020","XX公司")
	d mResumeA.CloneWorkExperience()
	d mResumeA.SetWorkExperienceObject("2010-2011","腾讯")
	
	# dim mResumeB as PHA.YX.Design.Prototype.Resume
	s mResumeB = mResumeA.%ConstructClone()
	d mResumeB.SetPersonalInfo("男","31")
	d mResumeB.CloneWorkExperience()
	d mResumeB.SetWorkExperienceObject("2011-2012","阿里")
	
	# dim mResumeC as PHA.YX.Design.Prototype.Resume
	s mResumeC =mResumeA.%ConstructClone()
	d mResumeC.SetWorkExperience("2017-2020","SS公司")
	d mResumeC.CloneWorkExperience()
	d mResumeC.SetWorkExperienceObject("2012-2013","百度")
	
	d mResumeA.Display()
	d mResumeB.Display()
	d mResumeC.Display()
}

结果发现，把引用字段work的值也修改成功。

DHC-APP>dclass(PHA.YX.Design.Program).PrototypeExampleDeep()
姚鑫 男 30
工作经历：2015-2020 XX公司
工作经历Object：2010-2011 腾讯
姚鑫 男 31
工作经历：2015-2020 XX公司
工作经历Object：2011-2012 阿里
姚鑫 男 30
工作经历：2017-2020 SS公司
工作经历Object：2012-2013 百度

完整示例

简历类(复制类)

Class PHA.YX.Design.Prototype.Resume Extends %RegisteredObject
{

Property name As %String [ Private ];

Property sex As %String [ Private ];

Property age As %String [ Private ];

Property timeArea As %String [ Private ];

Property company As %String [ Private ];

Property work As WorkExperience [ Private ];

Method %OnNew(name As %String) As %Status [ Private, ServerOnly = 1 ]
{
	s $this.name = name
	s ..work =class(WorkExperience).%New()
	Quit $$$OK
}

Method CloneWorkExperience()
{
	s ..work = ..work.%ConstructClone()
}

Method SetPersonalInfo(sex As %String, age As %String)
{
	s $this.sex=sex
	s $this.age=age
}

Method SetWorkExperience(timeArea As %String, company As %String)
{
	s $this.timeArea=timeArea
	s $this.company=company
}

Method SetWorkExperienceObject(workDate As %String, company As %String)
{
	d ..work.workDateSet(workDate)
	d ..work.companySet(company)
}

Method Display()
{
	w ..name _ " " _ ..sex _ " " _ ..age,!
	w "工作经历：" _ ..timeArea _ " " _ ..company,!
	w "工作经历Object：" _ ..work.workDateGet() _ " " _ ..work.companyGet(),!
}

}

对象类（工作经验类）

Class PHA.YX.Design.Prototype.WorkExperience Extends %RegisteredObject
{

Property workDate As %String [ Private ];

Method workDateGet() As %String [ ServerOnly = 1 ]
{
	Quit i%workDate
}

Method workDateSet(Arg As %String) As %Status [ ServerOnly = 1 ]
{
	s i%workDate = Arg
	Quit $$$OK
}

Property company As %String [ Private ];

Method companyGet() As %String [ ServerOnly = 1 ]
{
	Quit i%company
}

Method companySet(Arg As %String) As %Status [ ServerOnly = 1 ]
{
	s i%company = Arg
	Quit $$$OK
}

}

调用

/// dclass(PHA.YX.Design.Program).PrototypeExamplePrimary() 
ClassMethod PrototypeExamplePrimary()
{
	s mResumeA =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeA.SetPersonalInfo("男","30")
	d mResumeA.SetWorkExperience("2015-2020","XX公司")
	
	s mResumeB =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeB.SetPersonalInfo("男","30")
	d mResumeB.SetWorkExperience("2015-2020","XX公司")
	
	s mResumeC =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeC.SetPersonalInfo("男","30")
	d mResumeC.SetWorkExperience("2015-2020","XX公司")
	
	d mResumeA.Display()
	d mResumeB.Display()
	d mResumeC.Display()
}

/// dclass(PHA.YX.Design.Program).PrototypeExampleIntermediate() 
ClassMethod PrototypeExampleIntermediate()
{
	s mResumeA =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeA.SetPersonalInfo("男","30")
	d mResumeA.SetWorkExperience("2015-2020","XX公司")
	
	# dim mResumeB as PHA.YX.Design.Prototype.Resume
	s mResumeB = mResumeA
	d mResumeB.SetPersonalInfo("男","31")
	
	# dim mResumeC as PHA.YX.Design.Prototype.Resume
	s mResumeC = mResumeA
	d mResumeC.SetWorkExperience("2017-2020","SS公司")
	d mResumeA.Display()
	d mResumeB.Display()
	d mResumeC.Display()
}

/// dclass(PHA.YX.Design.Program).PrototypeExampleSenior() 
ClassMethod PrototypeExampleSenior()
{
	s mResumeA =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeA.SetPersonalInfo("男","30")
	d mResumeA.SetWorkExperience("2015-2020","XX公司")
	
	# dim mResumeB as PHA.YX.Design.Prototype.Resume
	s mResumeB = mResumeA.%ConstructClone()
	d mResumeB.SetPersonalInfo("男","31")
	
	# dim mResumeC as PHA.YX.Design.Prototype.Resume
	s mResumeC =mResumeA.%ConstructClone()
	d mResumeC.SetWorkExperience("2017-2020","SS公司")
	
	d mResumeA.Display()
	d mResumeB.Display()
	d mResumeC.Display()
}

/// dclass(PHA.YX.Design.Program).PrototypeExampleShallow() 
ClassMethod PrototypeExampleShallow()
{
	s mResumeA =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeA.SetPersonalInfo("男","30")
	d mResumeA.SetWorkExperience("2015-2020","XX公司")
	d mResumeA.SetWorkExperienceObject("2010-2011","腾讯")
	
	# dim mResumeB as PHA.YX.Design.Prototype.Resume
	s mResumeB = mResumeA.%ConstructClone()
	d mResumeB.SetPersonalInfo("男","31")
	d mResumeB.SetWorkExperienceObject("2011-2012","阿里")
	
	# dim mResumeC as PHA.YX.Design.Prototype.Resume
	s mResumeC =mResumeA.%ConstructClone()
	d mResumeC.SetWorkExperience("2017-2020","SS公司")
	d mResumeC.SetWorkExperienceObject("2012-2013","百度")
	
	d mResumeA.Display()
	d mResumeB.Display()
	d mResumeC.Display()
}

/// dclass(PHA.YX.Design.Program).PrototypeExampleDeep() 
ClassMethod PrototypeExampleDeep()
{
	s mResumeA =class(PHA.YX.Design.Prototype.Resume).%New("姚鑫")
	d mResumeA.SetPersonalInfo("男","30")
	d mResumeA.SetWorkExperience("2015-2020","XX公司")
	d mResumeA.CloneWorkExperience()
	d mResumeA.SetWorkExperienceObject("2010-2011","腾讯")
	
	# dim mResumeB as PHA.YX.Design.Prototype.Resume
	s mResumeB = mResumeA.%ConstructClone()
	d mResumeB.SetPersonalInfo("男","31")
	d mResumeB.CloneWorkExperience()
	d mResumeB.SetWorkExperienceObject("2011-2012","阿里")
	
	# dim mResumeC as PHA.YX.Design.Prototype.Resume
	s mResumeC =mResumeA.%ConstructClone()
	d mResumeC.SetWorkExperience("2017-2020","SS公司")
	d mResumeC.CloneWorkExperience()
	d mResumeC.SetWorkExperienceObject("2012-2013","百度")
	
	d mResumeA.Display()
	d mResumeB.Display()
	d mResumeC.Display()
}

思考

用深复制实现，Java，Python，C#，连接Caché数据库（有连接属性，连接时间），Caché数据库持有SQL数据库连接（有连接属性，连接时间）。感兴趣的同学实现后可以发我一起参考下。