建造者模式（Swift 实现）

Builder 建造者模式

Extracting the instance’s building code from the instance’s class, and put the code into a “Builder” object to do the build work. So we can build different complex instance by using different composition of the builder method. Besides, Add a “director” to manage the calling form client.

将对象的构造代码从对象的产品类代码中抽离出来，将这些代码放置在一个名为 “生成器” 的独立对象中。 所以，我们可以通过在建造方法中使用不同的组合，来创建不同的复杂实例。并且，增加一个 “指挥者” 来管理那些来自外界客户对调用。

// Director
class HouseDirector{
    
    var builder: HouseBuilder
    init (builder: HouseBuilder) {
    
        self.builder = builder
    }
    func changeBuilder(bulider: HouseBuilder) {
    
        self.builder = bulider
    }
    // The function "make" define the house must built by some componets. 
    func make(type: String) {
    
        builder.reset()
        if type == "simple" {
    
            builder.buildA()
        } else {
    
            builder.buildB()
            builder.buildC()
        }
    }
}

// Builder
protocol HouseBuilder {
    
    func reset()
    func buildA()
    func buildB()
    func buildC()
}

class Builder1: HouseBuilder {
    
    private var result: Product1?
    func reset() {
    
        result = Product1()
    }
    func buildA() {
    
        
    }
    func buildB() {
    
        
    }
    func buildC() {
    
        
    }
    func getResult() -> Product1? {
    
        return result
    }
}

class Builder2: HouseBuilder {
    
    private var result: Product2?
    func reset() {
    
        result = Product2()
    }
    func buildA() {
    
        
    }
    func buildB() {
    
        
    }
    func buildC() {
    
        
    }
    func getResult() -> Product2? {
    
        return result
    }
}

class Product1 {
    
    
}

class Product2 {
    
    
}

let b = Builder1()
let director = HouseDirector(builder: b)
director.make(type: "complex")