Bridge模式(桥接模式)

什么是桥接模式？

• 桥接模式即将类的功能层次结构与实现层次结构分离。
• 作用是在类的功能层次结构和类的实现层次结构之间搭建桥梁
• 当想要增加功能时，只需要在类的功能层次结构一侧添加类即可，不必对类的实现层次结构做任何修改。而且，增加后的功能可以被所有的实现使用

示范代码(bridge.go)

画一个红色圆型和黄色圆型

package Bridge

import (
	"fmt"
)

type Draw interface {
	DrawCircle(radius, x, y int)
}

type RedCircle struct {
	Draw
}

func (g *RedCircle) DrawCircle(radius, x, y int) {
	fmt.Printf("color:red\nradius:%d\nx:%d\ny:%d\n", radius, x, y)
}

type YellowCircle struct {
	Draw
}

func (g *YellowCircle) DrawCircle(radius, x, y int) {
	fmt.Printf("color:yellow\nradius:%d\nx:%d\ny:%d\n", radius, x, y)
}

type Shape struct {
	draw Draw
	Shape func(Draw)
}

func (s *Shape) Shape(d Draw) {
	s.draw = d
}

type Circle struct {
	shape  Shape
	x      int
	y      int
	radius int
}

func (c *Circle) Constructor(x int, y int, radius int, draw Draw) {
	c.x = x
	c.y = y
	c.radius = radius
	c.shape.Shape(draw)
}

func (c *Circle) Cook() {
	c.shape.draw.DrawCircle(c.radius, c.x, c.y)
}

测试用例(bridge_test.go)

package Bridge

import (
	"fmt"
	"testing"
)

func TestCircle_Cook(t *testing.T) {
	redCircle := Circle{}
	redCircle.Constructor(0, 10, 5, &RedCircle{})
	yellowCicle := Circle{}
	yellowCicle.Constructor(10, 0, 5, &YellowCircle{})
	redCircle.Cook()
	fmt.Println()
	yellowCicle.Cook()
}