组合在 Swift 中的实现
Composite is a structural design pattern that allows composing objects into a tree-like structure and work with the it as if it was a singular object.
Composite became a pretty popular solution for the most problems that require building a tree structure. Composite's great feature is the ability to run methods recursively over the whole tree structure and sum up the results.
在 Swift 中使用模式
Usage examples: The Composite pattern is pretty common in Swift code. It's often used to represent hierarchies of user interface components or the code that works with graphs.
Identification: The composite is easy to recognize by behavioral methods taking an instance of the same abstract/interface type into a tree structure.