DesignPatternBridge桥接模式
桥接（Bridge）是用于把抽象化与实现化解耦，使得二者可以独立变化。这种类型的设计模式属于结构型模式，它通过提供抽象化和实现化之间的桥接结构，来实现二者的解耦。
意图: 将抽象部分与实现部分分离，使它们都可以独立的变化
管方代码
package bridge
import "fmt"
type AbstractMessage interface {
SendMessage(text, to string)
}
type MessageImplementer interface {
Send(text, to string)
}
type MessageSMS struct{}
func ViaSMS() MessageImplementer {
return &MessageSMS{}
}
func (*MessageSMS) Send(text, to string) {
fmt.Printf("send %s to %s via SMS", text, to)
}
type MessageEmail struct{}
func ViaEmail() MessageImplementer {
return &MessageEmail{}
}
func (*MessageEmail) Send(text, to string) {
fmt.Printf("send %s to %s via Email", text, to)
}
type CommonMessage struct {
method MessageImplementer
}
func NewCommonMessage(method MessageImplementer) *CommonMessage {
return &CommonMessage{
method: method,
}
}
func (m *CommonMessage) SendMessage(text, to string) {
m.method.Send(text, to)
}
type UrgencyMessage struct {
method MessageImplementer
}
func NewUrgencyMessage(method MessageImplementer) *UrgencyMessage {
return &UrgencyMessage{
method: method,
}
}
func (m *UrgencyMessage) SendMessage(text, to string) {
m.method.Send(fmt.Sprintf("[Urgency] %s", text), to)
}
测试代码
package bridge
func ExampleCommonSMS() {
m := NewCommonMessage(ViaSMS())
m.SendMessage("have a drink?", "bob")
// Output:
// send have a drink? to bob via SMS
}
func ExampleCommonEmail() {
m := NewCommonMessage(ViaEmail())
m.SendMessage("have a drink?", "bob")
// Output:
// send have a drink? to bob via Email
}
func ExampleUrgencySMS() {
m := NewUrgencyMessage(ViaSMS())
m.SendMessage("have a drink?", "bob")
// Output:
// send [Urgency] have a drink? to bob via SMS
}
func ExampleUrgencyEmail() {
m := NewUrgencyMessage(ViaEmail())
m.SendMessage("have a drink?", "bob")
// Output:
// send [Urgency] have a drink? to bob via Email
}
毛哥通俗讲解
- 突然想学画画，想用红色的笔画个压缩
- 学习一段时间之后，对于自己的审美有严格要求了
- 这个笔有大号小号之分，颜色也有了色彩差别
UML图
代码实现
package my
import "fmt"
// 抽象
type Pen interface {
SetColor(color Color)
Draw(what string)
}
// 扩充抽象类
type BigPen struct {
PenType string
Color Color
}
func NewBigPen() *BigPen {
return &BigPen{PenType:"big_pen"}
}
func (bp *BigPen) SetColor(c Color) {
bp.Color = c
}
func (bp *BigPen) Draw(what string) {
bp.Color.BePaint(bp.PenType, what)
}
type SmallPen struct {
Color Color
PenType string
}
func NewSmallPen() *SmallPen {
return &SmallPen{PenType:"small_pen"}
}
func (sp *SmallPen) SetColor(c Color) {
sp.Color = c
}
func (sp *SmallPen) Draw(what string) {
sp.Color.BePaint(sp.PenType, what)
}
// 实现类
type Color interface {
BePaint(penType string, what string)
}
// 红色
type Red struct {
ColorType string
}
func NewRed() *Red {
return &Red{ColorType:"红色"}
}
func (r *Red) BePaint(penType string, what string) {
fmt.Println(fmt.Sprintf("型号笔->%s, 颜色-> %s,实物-> %s", penType, r.ColorType, what))
}
type Green struct {
ColorType string
}
func NewGreen() *Green {
return &Green{ColorType:"绿色"}
}
func (g *Green) BePaint(penType string, what string) {
fmt.Println(fmt.Sprintf("型号笔->%s, 颜色-> %s,实物-> %s", penType, g.ColorType, what))
}
func TTmain() {
// 红色的大好笔画亚索
bp := NewBigPen()
bp.SetColor(NewRed())
bp.Draw("亚索")
// 绿色的小号笔画盲仔
sp := NewSmallPen()
sp.SetColor(NewGreen())
sp.Draw("盲仔")
}
# 通过ttmain测试输出
型号笔->big_pen, 颜色-> 红色,实物-> 亚索
型号笔->small_pen, 颜色-> 绿色,实物-> 盲仔
写法要点
最后具体实现落在了bepaint()上