GO设计模式04工厂方法模式

Posted 2021-06-26 XY丶YX

代码：

package main

import (
	"fmt"
)

//Operator 是被封装的实际类接口
type Operator interface {
	SetA(int)
	SetB(int)
	Result() int
}

//OperatorBase 是Operator 接口实现的基类，封装公用方法
type OperatorBase struct {
	a, b int
}

//SetA 设置 A
func (o *OperatorBase) SetA(a int) {
	o.a = a
}

//SetB 设置 B
func (o *OperatorBase) SetB(b int) {
	o.b = b
}

//----------------------------------------------------------------------------
//PlusOperator Operator 的实际加法实现
type PlusOperator struct {
	*OperatorBase
}

//Result 获取结果
func (o PlusOperator) Result() int {
	return o.a + o.b
}

//----------------------------------------------------------------------------
//MinusOperator Operator 的实际减法实现
type MinusOperator struct {
	*OperatorBase
}

//Result 获取结果
func (o MinusOperator) Result() int {
	return o.a - o.b
}

//----------------------------------------------------------------------------
//OperatorFactory 是工厂接口
type OperatorFactory interface {
	Create() Operator
}

//PlusOperatorFactory 是 PlusOperator 的工厂类
type PlusOperatorFactory struct{}

func (p PlusOperatorFactory) Create() Operator {
	return &PlusOperator{
		OperatorBase: &OperatorBase{},
	}
}

//MinusOperatorFactory 是 MinusOperator 的工厂类
type MinusOperatorFactory struct{}

func (m MinusOperatorFactory) Create() Operator {
	return &MinusOperator{
		OperatorBase: &OperatorBase{},
	}
}

//----------------------------------------------------------------------------
func compute(factory OperatorFactory, a, b int) int {
	op := factory.Create()
	op.SetA(a)
	op.SetB(b)
	return op.Result()
}

func main() {
	fmt.Println("hello")
	factory1 := PlusOperatorFactory{}
	if compute(factory1, 1, 2) != 3 {
		fmt.Println("error with factory method pattern")
	}
	fmt.Println("success1")
	factory2 := MinusOperatorFactory{}
	if compute(factory2, 4, 2) != 2 {
		fmt.Println("error with factory method pattern")
	}
	fmt.Println("success2")
}