原 大话设计模式(golang) 五、工厂方法模式

模式特点:定义一个用于创建对象的接口,让子类决定实例化哪一个类。这使得一个类的实例化延迟到其子类。
程序实例:计算器。

package main
import (
	"fmt"
)
type Operation struct {
	a float64
	b float64
}
type OperationI interface {
	GetResult() float64
	SetA(float64)
	SetB(float64)
}
func (op *Operation) SetA(a float64) {
	op.a = a
}
func (op *Operation) SetB(b float64) {
	op.b = b
}
type AddOperation struct {
	Operation
}
func (this *AddOperation) GetResult() float64 {
	return this.a + this.b
}
type SubOperation struct {
	Operation
}
func (this *SubOperation) GetResult() float64 {
	return this.a - this.b
}
type MulOperation struct {
	Operation
}
func (this *MulOperation) GetResult() float64 {
	return this.a * this.b
}
type DivOperation struct {
	Operation
}
func (this *DivOperation) GetResult() float64 {
	return this.a / this.b
}
type IFactory interface {
	CreateOperation() Operation
}
type AddFactory struct {
}
func (this *AddFactory) CreateOperation() OperationI {
	return &(AddOperation{})
}
type SubFactory struct {
}
func (this *SubFactory) CreateOperation() OperationI {
	return &(SubOperation{})
}
type MulFactory struct {
}
func (this *MulFactory) CreateOperation() OperationI {
	return &(MulOperation{})
}
type DivFactory struct {
}
func (this *DivFactory) CreateOperation() OperationI {
	return &(DivOperation{})
}
func main() {
	fac := &(AddFactory{})
	oper := fac.CreateOperation()
	oper.SetA(1)
	oper.SetB(2)
	fmt.Println(oper.GetResult())
}

本文来自:开源中国博客

感谢作者:平凡之路

查看原文:原 大话设计模式(golang) 五、工厂方法模式

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