我是一个iOS开发人员,有几年使用swift的经验,但很少使用PAT的。。。
构建器依赖于工厂传递给他的一些变量,但是这些变量是应用程序级别的,所以,要提取这个逻辑并将其放入我的库中,我需要使用一个泛型引用,因为我希望以面向协议的编程方式工作,所以它是一个关联类型。
// The item that i want to receive from my factory
protocol Item {
var content: String { get }
}
// This is the Builder interface that the Factory consumes
protocol Builder {
// The Abstract Parameters that the Application should define
associatedtype Parameters
func build(_ parameters: Parameters) -> Item?
}
// The BusinessResource of my library
protocol BusinessResource { }
// The Factory that consumes the Builders
protocol Factory {
associatedtype FactoryBuilder: Builder
var parameters: FactoryBuilder.Parameters { get }
func make(from businessResource: BusinessResource) -> Item?
}
// The generic implementation of my Factory
extension Factory {
func make(from businessResource: BusinessResource) -> Item? {
guard let builder = businessResource as? FactoryBuilder else {
return nil
}
return builder.build(self.parameters)
}
}
在这一点上一切看起来都很好。
我有两个协议,它们绑定在一起,共享一个通用类型(生成器参数)。
// The concrete parameters of the Application Factory
struct ConcreteParameters {
let string: String
}
// The Builder interface restricting Parameters to ConcreteParameters
protocol BindedBuilder: Builder where Parameters == ConcreteParameters {
}
// The Factory interface restricting Parameters to ConcreteParameters
protocol BindedFactory: AbstractFactory where FactoryParameters: ConcreteParameters {
}
到目前为止,还不错。一切看起来都就绪,我开始认为这可以工作,所以现在我尝试在应用程序上实现一个具体的工厂,以尝试这是否真的有效。
// The concrete output of my Builder
struct ConcreteItem: Item {
var content: String
}
// The concrete BusinessResource that i get from my library
struct ConcreteObject: BusinessResource {
let string: String
}
// The decoration extension that makes ConcreteObject compliant with Builder
extension ConcreteObject: Builder {
typealias Parameters = ConcreteParameters
func build(_ parameters: ConcreteParameters) -> Item? {
return ConcreteItem(content: parameters.string + self.string)
}
}
// The real Factory inside my app
class ConcreteFactory: BindedFactory {
typealias FactoryBuilder = BindedBuilder
var parameters: ConcreteParameters {
return ConcreteParameters(string: "Hello ")
}
}
let item = ConcreteFactory().make(from: ConcreteObject(string: "world!"))
print(item ?? "NOT WORKING")
在这一点上有些东西断裂了。。。我得到这个错误:
[
AbstractFactor是当前工厂
]
是个虫子??
我真的不知道怎么解决这个问题。。。
