Go語言的多態(Polymorphism)

Go的多態(Polymorphism) 是怎么實現的？

這幾天查資料下面的代碼寫的很容易看懂。

看代碼吧。不多解釋了.

package main

import "fmt"

type AnimalIF interface {
    Sleep()
    Age() int
    Type() string
}
type Animal struct {
    MaxAge int
}

/*=======================================================*/

type Cat struct {
    Animal Animal
}

func (this *Cat) Sleep() {
    fmt.Println("Cat need sleep")
}
func (this *Cat) Age() int {
    return this.Animal.MaxAge
}
func (this *Cat) Type() string {
    return "Cat"
}

/*=======================================================*/

type Dog struct {
    Animal Animal
}

func (this *Dog) Sleep() {
    fmt.Println("Dog need sleep")
}
func (this *Dog) Age() int {
    return this.Animal.MaxAge
}
func (this *Dog) Type() string {
    return "Dog"
}

/*=======================================================*/

func Factory(name string) AnimalIF {
    switch name {
    case "dog":
        return &Dog{Animal{MaxAge: 20}}
    case "cat":
        return &Cat{Animal{MaxAge: 10}}
    default:
        panic("No such animal")
    }
}

/*======================================================*/

func main() {
    animal := Factory("dog")
    animal.Sleep()
    fmt.Printf("%s max age is: %d", animal.Type(), animal.Age())
}

> Output:
Dog need sleep
Dog max age is: 20