命令模式
命令模式（Command Pattern）是一种数据驱动的设计模式，它属于行为型模式.
请求以命令的形式包裹在对象中，并传给调用对象。调用对象寻找可以处理该命令的合适的对象，并把该命令传给相应的对象，该对象执行命令.
优点 和 缺点
优点:
- 降低系统的耦合度。命令模式能将调用操作的对象与实现该操作的对象解耦.
缺点:
- 使用命令模式可能会导致某些系统有过多的具体命令类
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| type Stock struct {
name string
quantity int
}
func (stock *Stock) Set(name string, quantity int) {
stock.name = name
stock.quantity = quantity
}
func (stock *Stock) Buy(s Stock) {
stock.name = s.name
stock.quantity = s.quantity
fmt.Printf("Buy stock %s, quantity:%d \n", s.name, s.quantity)
}
func (stock Stock) Sell(s Stock) {
stock.name = s.name
stock.quantity = s.quantity
fmt.Printf("Sell stock %s, quantity:%d \n", s.name, s.quantity)
}
type Order interface {
Execute()
}
type BuyStock struct {
stock Stock
}
func (buy BuyStock) Execute() {
fmt.Println("execute in buy command")
buy.stock.Buy(buy.stock)
}
type SellStock struct {
stock Stock
}
func (sell SellStock) Execute() {
fmt.Println("execute in sell command")
sell.stock.Sell(sell.stock)
}
type Broker struct {
order Order
}
func (broker *Broker) SetOrder(order Order) {
fmt.Printf("set order:%v\n", order)
broker.order = order
}
func (broker Broker) Call() {
fmt.Println("call in broker")
broker.order.Execute()
}
|
