去和面向对象的范例

Question

Given the following interface...

type Person struct {
    name, gender string
}

type Citizen interface {
    Create(name string) Citizen
    GetName() string
    GetGender() String
    SayHello() String
}

... and the following Male and Female implementations:

type Male Person

func (m *Male) Create(name) Citizen {
    return &Person{name, "male"}
}

func (m *Male) GetName() string {
    return m.name
}

func (m *Male) GetGender() string {
    return m.gender
}

func (m *Male) SayHello() string {
    return "Hello (male voice)"
}

type Female Person

func (f *Female) Create(name) Citizen {
    return &Person{name, "female"}
}

func (f *Female) GetName() string {
    return f.name
}

func (f *Female) GetGender() string {
    return f.gender
}

func (m *Female) SayHello() string {
    return "Hello (female voice)"
}

func main() {
    var p1 Person = &Male{}
    var p2 Person = &Female{}

    p1 = p1.Create("Joe")
    p2 = p2.Create("Heidi")

    log.Printf("%s is a %s",p1.GetName(), p1.GetGender())
    log.Printf("%s says %s",p1.GetName(), p1.SayHello())
    log.Printf("%s is a %s",p2.GetName(), p2.GetGender())
    log.Printf("%s says %s",p2.GetName(), p2.SayHello())
}

As only Create is gender-specific, is there a way to let Male and Female inherit a common implementation of methods GetName and GetGender?

Answer 1

Embed Person in the Male and Female types and push the base methods up to Person.

type Male struct {
    Person
}

type Female struct {
    Person
}

func (m *Person) GetName() string {
    return m.Name
}

func (m *Person) GetGender() string {
    return m.Gender
}

func main() {
    var c Citizen
    c = CreateMale("Joe")
    fmt.Println(c.GetName(), c.GetGender(), "
", c.SayHello())
    c = CreateFemale("Jane")
    fmt.Println(c.GetName(), c.GetGender(), "
", c.SayHello())
}

See full example here: https://play.golang.org/p/GZcG-n_YpM

This uses the interface Citizen instead of the type Person in the assignment, so let me know if that isn't what you are looking for.