ios - 如何重构 swift 代码以将协议(protocol)和结构类型作为方法参数

Question

我有 2 个有很多共同点的函数，我想重构我的代码以删除重复的逻辑，但是不同的是类型，特别是协议(protocol)和结构类型。我现在可以考虑的方式是，为了重构它，我将有 1 个通用方法将一种协议(protocol)类型作为参数，以及一种结构类型，其限制是结构类型必须实现协议(protocol)“DataDictionaryStore” .并将返回作为参数 1 传入的协议(protocol)类型的数组

我曾尝试使用泛型来实现这一点，但根据我的理解，在使用泛型时您仍然将实例作为参数传递，而不是实际类型本身。

我想在下面的代码中重构的方法是“articles()”和“authors()”

这是代码(可以复制到 playground Xcode 7+):

import Foundation

protocol Article {
    var headline: NSString? { get }
}

protocol Author {
    var firstName: NSString? { get }
}

protocol DataDictionaryStore {

    init(dataDictionary: NSDictionary)
}

struct CollectionStruct {

    let arrayOfModels: [NSDictionary]

    //This function is identical to authors() except for return type [Article], and 'ArticleStruct'
    func articles() -> [Article] {

        var articlesArray = [Article]()

        for articleDict in arrayOfModels {
            let articleStruct = ArticleStruct(dataDictionary: articleDict)
            articlesArray.append(articleStruct)
        }
        return articlesArray
    }

    func authors() -> [Author] {

        var authorsArray = [Author]()

        for authorDict in arrayOfModels {
            let authorStruct = AuthorStruct(dataDictionary: authorDict)
            authorsArray.append(authorStruct)
        }
        return authorsArray
    }
}

struct ArticleStruct : Article, DataDictionaryStore {

    var internalDataDictionary: NSDictionary
    init(dataDictionary: NSDictionary) {
        internalDataDictionary = dataDictionary
    }
    var headline: NSString? { return (internalDataDictionary["headline"] as? NSString) }
}

struct AuthorStruct : Author, DataDictionaryStore {

    var internalDataDictionary: NSDictionary
    init(dataDictionary: NSDictionary) {
        internalDataDictionary = dataDictionary
    }
    var firstName: NSString? { return (internalDataDictionary["firstName"] as? NSString) }
}

var collStruct = CollectionStruct(arrayOfModels: [NSDictionary(objects: ["object1", "object2"], forKeys: ["key1", "headline"])])

print(collStruct)
var articles = collStruct.articles()
print(articles)
for article in articles {
    print(article.headline)
}

如果有另一种方法来重构它以删除重复的逻辑，欢迎所有建议。

Answer 1

这不完全是您问题的答案，但这可能足以让您满意地简化它:

func articles() -> [Article] {
    return arrayOfModels.map(ArticleStruct.init)
}

func authors() -> [Author] {
    return arrayOfModels.map(AuthorStruct.init)
}