Golang组合模式实现对象树管理

<strong>type Component interface {
    Print(indent string)
    GetSize() int
}</strong>

<strong>type File struct {
    name string
    size int
}

func (f *File) Print(indent string) {
    fmt.Println(indent + f.name + " (" + strconv.Itoa(f.size) + "KB)")
}

func (f *File) GetSize() int {
    return f.size
}</strong>

<strong>type Directory struct {
    name       string
    components []Component
}

func (d *Directory) Add(comp Component) {
    d.components = append(d.components, comp)
}

func (d *Directory) Print(indent string) {
    fmt.Println(indent + d.name + "/")
    for _, comp := range d.components {
        comp.Print(indent + "  ")
    }
}

func (d *Directory) GetSize() int {
    total := 0
    for _, comp := range d.components {
        total += comp.GetSize()
    }
    return total
}</strong>

<strong>root := &Directory{name: "root"}
docs := &Directory{name: "docs"}
src := &Directory{name: "src"}

file1 := &File{name: "readme.txt", size: 5}
file2 := &File{name: "main.go", size: 10}
file3 := &File{name: "utils.go", size: 8}

docs.Add(file1)
src.Add(file2)
src.Add(file3)
root.Add(docs)
root.Add(src)

root.Print("")
fmt.Printf("Total size: %d KB\n", root.GetSize())</strong>