[设计模式 Go实现] 结构型～装饰模式

package decorator

type Component interface {
    Calc() int
}

type ConcreteComponent struct{}

func (*ConcreteComponent) Calc() int {
    return 0
}

type MulDecorator struct {
    Component
    num int
}

func WarpMulDecorator(c Component, num int) Component {
    return &MulDecorator{
        Component: c,
        num:       num,
    }
}

func (d *MulDecorator) Calc() int {
    return d.Component.Calc() * d.num
}

type AddDecorator struct {
    Component
    num int
}

func WarpAddDecorator(c Component, num int) Component {
    return &AddDecorator{
        Component: c,
        num:       num,
    }
}

func (d *AddDecorator) Calc() int {
    return d.Component.Calc() + d.num
}

package decorator

import "fmt"

func ExampleDecorator() {
    var c Component = &ConcreteComponent{}
    c = WarpAddDecorator(c, 10)
    c = WarpMulDecorator(c, 8)
    res := c.Calc()

    fmt.Printf("res %d\n", res)
    // Output:
    // res 80
}