Golang实现组合节点树形处理方法

type Component interface {
    GetName() string
    GetSize() int64
    Print(indent string)
    Add(Component) error // 可选：仅容器需支持，叶子可返回错误
}

type File struct {
    name string
    size int64
}

func (f *File) GetName() string { return f.name }
func (f *File) GetSize() int64  { return f.size }
func (f *File) Print(indent string) {
    fmt.Printf("%s? %s (%d bytes)\n", indent, f.name, f.size)
}
func (f *File) Add(_ Component) error {
    return errors.New("cannot add to file")
}

type Folder struct {
    name     string
    children []Component
}

func (f *Folder) GetName() string { return f.name }
func (f *Folder) GetSize() int64 {
    var total int64
    for _, c := range f.children {
        total += c.GetSize()
    }
    return total
}
func (f *Folder) Print(indent string) {
    fmt.Printf("%s? %s (total: %d bytes)\n", indent, f.name, f.GetSize())
    for _, c := range f.children {
        c.Print(indent + "  ")
    }
}
func (f *Folder) Add(c Component) error {
    f.children = append(f.children, c)
    return nil
}

root := &Folder{name: "project"}
src := &Folder{name: "src"}
src.Add(&File{name: "main.go", size: 1024})
src.Add(&File{name: "utils.go", size: 512})

root.Add(src)
root.Add(&File{name: "README.md", size: 2048})

root.Print("") // 自动递归打印整棵树
fmt.Printf("Total size: %d\n", root.GetSize()) // 自动聚合