Builder: Problem
Example: a complex object that requires laborious, step-by-step initialization of many fields and nested objects
一個複雜物件的建立通常由多個部分組成，這些部分的組合經常變化
Builder: Solution
Extract the object construction code out of its own class and move it to separate objects called builders
Further extract the series of calls to the builder steps into a separate class called director
進一步將對構建器步驟的一系列呼叫提取到一個名為 director 的單獨類中
– The director defines the order in which to execute the building steps, while the builder provides concrete implementation
– Having a director class is not strictly necessary
– Might be a good place to put various construction routines for reuse
– Completely hiding the details of construction from the client code
– director 定義執行構建步驟的順序，而構建器提供具體的實現
– 擁有一個 director 類並不是絕對必要的
– 可能是放置各種構建例程以供重用的好地方
– 在客戶端程式碼中完全隱藏構建細節
Builder: Implementation
- Clearly define the common construction steps for building all available product representations
- Declare these steps in the base builder interface
- Create a concrete builder class for each of the product representations and implement their construction steps, and also implement a method for fetching the result of construction
- Consider creating a director class (not necessarily)
- The client code creates both the builder and the director objects
- The construction result can be obtained directly from the director only if all products follow the same interface; otherwise, the client should fetch the result from the builder
1.明確定義構建所有可用產品表示的常見構建步驟
2.在 base builder 介面中宣告這些步驟
3.為每個產品表示建立一個具體的 builder 類並實現它們的構造步驟，並實現一個獲取構造結果的方法
4.考慮建立一個 director 類（不一定）
5.客戶端程式碼會同時建立 builder 和 director 物件
6.只有當所有產品都遵循相同的介面時，才能直接從 director 獲得構造結果;否則，客戶端應從生成器中獲取結果
Prototype: Problem and Solution
Problem: creating an exact copy of an object
問題：建立物件的精確副本
– Some fields may not be visible from the outside
– The code becomes dependent on that class
– Sometimes you only know the interface but not the concrete class
– 某些欄位可能從外部不可見
– 程式碼變得依賴於該類
– 有時您只知道介面，而不知道具體的類
Solution: the Prototype pattern
– Delegating the cloning process to the actual objects being cloned
– A common interface for all objects supporting cloning, with a singleclone method
– An object supporting cloning is called a prototype
– 將克隆過程委託給正在克隆的實際物件
– 支援克隆的所有物件的通用介面，具有單個
– 支援克隆的物件稱為原型
Prototype: Example
Produce exact copies of geometric objects, without coupling the code to their classes
生成幾何物件的精確副本，而無需將程式碼耦合到其類
Note: a subclass may call the parent’s cloning method before copying its own field values to the resulting object.
注意：子類可以呼叫父級的克隆方法將自己的 Field 值複製到結果物件中。