桥接模式分离抽象部分和实现部分。使得两部分独立扩展。
桥接模式类似于策略模式，区别在于策略模式封装一系列算法使得算法可以互相替换。
策略模式使抽象部分和实现部分分离，可以独立变化。
bridge.go
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)
}
bridge_test.go
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
}