11、Caché 设计模式 - 抽象工厂模式

定义

提供一个创建一系列相关或相互依赖的接口，而无需制定它们具体的类。

优点

相比与简单工厂，没有违背开放封闭原则。

可直接创建产品即可。

结构图

描述

连接数据库SQL和Caché并且每个数据库映射的同张的表的类型是不同的。

完整示例

实体类

Class PHA.YX.Design.AbstractFactory.User Extends %RegisteredObject
{

Property ID As %String;

Method IDGet() As %String [ ServerOnly = 1 ]
{
	Quit i%ID
}

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

Property name As %String;

Method nameGet() As %String [ ServerOnly = 1 ]
{
	Quit i%name
}

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

}

Class PHA.YX.Design.AbstractFactory.Department Extends %RegisteredObject
{

Property ID As %String;

Method IDGet() As %String [ ServerOnly = 1 ]
{
	Quit i%ID
}

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

Property name As %String;

Method nameGet() As %String [ ServerOnly = 1 ]
{
	Quit i%name
}

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

}

抽象产品类

Class PHA.YX.Design.AbstractFactory.IDepartment Extends %RegisteredObject
{

Method Insert(department As Department)
{
}

Method GetDepartment(ID As %Integer)
{
}

}

Class PHA.YX.Design.AbstractFactory.IUser Extends %RegisteredObject
{

Method Insert(user As User)
{
}

Method GetUser(ID As %Integer)
{
}

}

具体产品类

User

Class PHA.YX.Design.AbstractFactory.SqlUser Extends IUser
{

Method Insert(user As User)
{
	w "在SQL中给User表添加一条记录",!
}

Method GetUser(ID As %Integer)
{
	w "在SQL中根据ID得到User表一条记录",!
}

ClassMethod CreatObject()
{
	qclass(PHA.YX.Design.AbstractFactory.SqlUser).%New()
}

}

Class PHA.YX.Design.AbstractFactory.CacheUser Extends IUser
{

Method Insert(user As User)
{
	w "在Cache中给User表添加一条记录",!
}

Method GetUser(ID As %Integer)
{
	w "在Cache中根据ID得到User表一条记录",!
}

ClassMethod CreatObject()
{
	qclass(PHA.YX.Design.AbstractFactory.CacheUser).%New()
}

}

Department

Class PHA.YX.Design.AbstractFactory.SqlDepartment Extends IDepartment
{

Method Insert(department As Department)
{
	w "在SQL中给Department表添加一条记录",!
}

Method GetDepartment(ID As %Integer)
{
	w "在SQL中根据ID得到Department表一条记录",!
}

ClassMethod CreatObject()
{
	qclass(PHA.YX.Design.AbstractFactory.SqlDepartment).%New()
}

}

Class PHA.YX.Design.AbstractFactory.CacheDepartment Extends IDepartment
{

Method Insert(department As Department)
{
	w "在Cache中给Department表添加一条记录",!
}

Method GetDepartment(ID As %Integer)
{
	w "在Cache中根据ID得到Department表一条记录",!
}

ClassMethod CreatObject()
{
	qclass(PHA.YX.Design.AbstractFactory.CacheDepartment).%New()
}

}

抽象工厂类

因为Caché 系统$反射方法没有创建对象的方法。所以采用了一种讨巧的方式.

$classmethod 可以直接调用静态方法。

通过给实体类创建一个静态方法返回该对象的实例。

直接用XECUTE命令直接反射，然后获取引用对象。

配置的字符串可以通过inc文件来制定，符合开放封闭原则，又可配置。

注意：本章使用的反射+配置实现访问程序

Include PHA.YX.Design.AbstractFactory.Data

Class PHA.YX.Design.AbstractFactory.DataAccess Extends %RegisteredObject
{

Parameter sqlDatabase = "Sql";

Parameter cacheDatabase = "Cache";

ClassMethod CreateUser() As IUser
{
	# dim mUser as PHA.YX.Design.AbstractFactory.IUser
	s classNmae = "PHA.YX.Design.AbstractFactory." _ ..#sqlDatabase _ "User"
	s mUser = $classmethod(classNmae,"CreatObject")
	q mUser
}

ClassMethod CreateDepartment() As IDepartment
{
	# dim mUser as PHA.YX.Design.AbstractFactory.IDepartment
	s classNmae = "PHA.YX.Design.AbstractFactory." _ ..#sqlDatabase _ "Department"
	s mUser = $classmethod(classNmae,"CreatObject")
	q mUser
}

ClassMethod CreateUserTwo() As IUser
{
	# dim mUser as PHA.YX.Design.AbstractFactory.IUser
	s classNmae = "PHA.YX.Design.AbstractFactory." _ $$$database _ "User"
	x ("(mUser) s mUser =class(" _ classNmae _ ").%New()", .mUser)
	q mUser
}

}

#define database "Cache"

思考

改写第一章思考生产电脑的例子。感兴趣的同学实现后可以发我一起参考下。