当前位置:网站首页>Golang anonymous structure member, named structure member, inheritance, composition

Golang anonymous structure member, named structure member, inheritance, composition

2020-11-07 23:04:47 lanyangsh

This article will introduce Inherit Combine These reuse concepts are in golang How is it embodied in .

stay golang in , Through anonymous struct members , Access to methods defined in anonymous structs , It's the so-called real Inherit .

Through named structural members , You can also access the methods defined in the struct , That's what's called Combine .

1. Anonymous struct members --- Inherit

Example 1

Structure A1 Contains anonymous structs A.

Definition A1 The variable of a1, adopt a1 visit A Methods .

package main

import (
    "fmt"
)

type A struct {
    
}

func (t *A) Print(){
    fmt.Println("I am A.")
}

type A1 struct {
    A
}

func main() {
    a1 := A1{}
    a1.Print()
    
}

output:

I am A.

As you can see from the output ,A1 Structural variables a1 Access to A Defined in a structure Print() Method . That is to say A1 Inherit 了 A.

Example 2

Defining interfaces Aer, It contains methods Print().

Then define AA1.
A1 Contains anonymous structs A.

Define test functions test(), The parameter is Aer Interface type .

package main

import (
    "fmt"
)


type Aer interface {
    Print()
}

type A struct {
    
}

func (t *A) Print(){
    fmt.Println("I am A.")
}

type A1 struct {
    A
}

func test(ai Aer) {
    ai.Print()
}

func main() {
    a1 := &A1{}

    test(a1)
    
}

output:

I am A.

You can see from the output that ,A1 Realized Aer Interface Print() Method .
And this is actually " Inherit " since A.

2. Members of a named structure -- Combine

Example 1

Structure A1 Contains the structure A Variable of type a.

Defining structure A The variable of a, Then use a Defining structure A1 Type variable
a1.
Finally through a1 visit a, Re pass a visit A Methods .

package main

import (
    "fmt"
)

type A struct {
    
}

func (t *A) Print(){
    fmt.Println("I am A.")
}

type A1 struct {
    a A
}

func main() {
    a := A{}
    a1 := A1{a}
    a1.a.Print()
    
}

output:

I am A.

As you can see from the output ,

Example 2

Defining interfaces Aer, It contains methods Print().

Then define AA1.
A1 Contains the structure A Type variable a As a member variable .

Last , test A1 Whether the interface is implemented Aer.

package main

import (
    "fmt"
)

type Aer interface {
    Print()
}


type A struct {
    
}

func (t *A) Print(){
    fmt.Println("I am A.")
}

type A1 struct {
    a A
}

func main() {
    a := A{}
    a1 := A1{a}
    var i interface {} = a1

    ai, ok := i.(Aer)
    if ok {
        fmt.Println("a1 implement Aer")
        ai.Print()
    } else {
        fmt.Println("a1 not implement Aer")
    }
    
}

output:

a1 not implement Aer

You can see through the results , Structure A1 There is no interface implemented Aer.
in other words , adopt Combine The way , No, " Inherit " Related methods .

3. Reference resources

Golang The inheritance of , multiple inheritance (struct)

版权声明
本文为[lanyangsh]所创,转载请带上原文链接,感谢