go语言设计模式 - 建造者模式

1、目录

• 1、目录
• 2、简介
  • 1. 解决的问题
• 3、实现
  • 1. 文件结构
  • 2. 具体实现
  • 3. 运行

2、简介

1. 解决的问题

Builder模式将复杂对象的构造与其表示分离开来，以便相同的构造过程能够建立不一样的表示。

3、实现

1. 文件结构

.
├── car
│   └── car.go
├── demoBuilder
│   └── demoBuilder.go
└── main.go
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2. 具体实现

./car/car.go

package car

type Speed float64

const (
	MPH Speed = 1
	KPH       = 1.60934
)

type Color string

const (
	BlueColor  Color = "blue"
	GreenColor       = "green"
	RedColor         = "red"
)

type Wheels string

const (
	SportsWheels Wheels = "sports"
	SteelWheels         = "steel"
)

type Builder interface {
	SetColor(Color) Builder
	SetWheels(Wheels) Builder
	SetTopSpeed(Speed) Builder
	Build() Interface
}

type Interface interface {
	Drive() error
	Stop() error
}
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./demoBuilder/demoBuilder.go

package demoBuilder

import (
	"fmt"
	"study/test/7/car"
)

type demoBuilder struct {
	name   string
	color  car.Color
	wheels car.Wheels
	speed  car.Speed
}

func NewBuilder(name string) demoBuilder {
	return demoBuilder{name: name}
}

type OptCarA struct {
	car demoBuilder
}

func (o OptCarA) Drive() error {
	fmt.Printf("The %s, %s, %f car is moving. builder is %s.\n",
		o.car.color, o.car.wheels, o.car.speed, o.car.name)
	return nil
}

func (o OptCarA) Stop() error {
	fmt.Printf("The %s, %s, %f car has stopped. builder is %s.\n",
		o.car.color, o.car.wheels, o.car.speed, o.car.name)
	return nil
}

func (c demoBuilder) SetColor(color car.Color) demoBuilder {
	c.color = color
	return c
}

func (c demoBuilder) SetWheels(wheels car.Wheels) demoBuilder {
	c.wheels = wheels
	return c
}

func (c demoBuilder) SetTopSpeed(speed car.Speed) demoBuilder {
	c.speed = speed
	return c
}

func (c demoBuilder) Build() OptCarA {
	fmt.Printf("build finish\n")
	return OptCarA{car: c}
}
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./main.go

package main

import (
	"study/test/7/car"
	"study/test/7/demoBuilder"
)

func main() {
	assembly := demoBuilder.NewBuilder("myCarBuilder").SetColor(car.RedColor)

	familyCar := assembly.SetWheels(car.SportsWheels).SetTopSpeed(50 * car.MPH).Build()
	familyCar.Drive()
	familyCar.Stop()

	sportsCar := assembly.SetWheels(car.SteelWheels).SetTopSpeed(150 * car.MPH).Build()
	sportsCar.Drive()
	sportsCar.Stop()
}
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3. 运行

[root@localhost gopath]# go run main.go 
build finish
The red, sports, 50.000000 car is moving. builder is myCarBuilder.
The red, sports, 50.000000 car has stopped. builder is myCarBuilder.
build finish
The red, steel, 150.000000 car is moving. builder is myCarBuilder.
The red, steel, 150.000000 car has stopped. builder is myCarBuilder.
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