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设计模式-桥接模式
source link: http://www.hi-roy.com/2019/12/12/设计模式-桥接模式/
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桥接模式核心原理是将抽象部分和实现部分分析，使二者可以独立的变化。再具体一点，当某个类型由于自身逻辑可以有两个或多个维度的变化，使用桥接模式可以令这些维度变化时不影响其他维度。再举个例子，手机——可以按照品牌来分类，比如苹果华为三星，也可以按照功能分类，比如拍照手机，游戏手机等等。
桥接模式有2个设计原则：
is-a
实例代码如下：
package main
import "fmt"
type phoneFeature interface {
showFeature()
}
type gamePhone struct{}
func (g gamePhone) showFeature() {
fmt.Printf("This phone is for play game!\n")
}
type cameraPhone struct{}
func (c cameraPhone) showFeature() {
fmt.Printf("This phone is for camera!\n")
}
type phoneBrand struct {
name string
feature phoneFeature
}
func (b phoneBrand) show() {
fmt.Printf("This is a %s phone!\n", b.name)
b.feature.showFeature()
}
func (b *phoneBrand) setFeature(phonefeature phoneFeature) {
b.feature = phonefeature
}
type huawei struct {
*phoneBrand
}
type apple struct {
*phoneBrand
}
func main() {
h := huawei{phoneBrand: &phoneBrand{name: "huawei"}}
a := apple{phoneBrand: &phoneBrand{name: "apple"}}
h.setFeature(cameraPhone{})
h.show()
a.setFeature(gamePhone{})
a.show()
}
这里我创建了2种类型的手机：游戏手机和拍照手机，2种品牌：华为和苹果。然后通过 phoneFeature 接口作为桥梁将这2者组合在一起，通过这种方法，不论以后是增加修改手机品牌还是类型，都不会影响到另一方了。
使用场景
- 类的抽象和实现都应该可以通过生成子类的方法加以扩充
- 对一个抽象的实现部分的修改应对客户不产生影响。
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