go-pattern-examples/behavior/16_state/state.go

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2020-04-21 17:50:21 +03:00
package state
import "fmt"
type Week interface {
Today()
Next(*DayContext)
}
type DayContext struct {
today Week
}
func NewDayContext() *DayContext {
return &DayContext{
today: &Sunday{},
}
}
func (d *DayContext) Today() {
d.today.Today()
}
func (d *DayContext) Next() {
d.today.Next(d)
}
type Sunday struct{}
func (*Sunday) Today() {
fmt.Printf("Sunday\n")
}
func (*Sunday) Next(ctx *DayContext) {
ctx.today = &Monday{}
}
type Monday struct{}
func (*Monday) Today() {
fmt.Printf("Monday\n")
}
func (*Monday) Next(ctx *DayContext) {
ctx.today = &Tuesday{}
}
type Tuesday struct{}
func (*Tuesday) Today() {
fmt.Printf("Tuesday\n")
}
func (*Tuesday) Next(ctx *DayContext) {
ctx.today = &Wednesday{}
}
type Wednesday struct{}
func (*Wednesday) Today() {
fmt.Printf("Wednesday\n")
}
func (*Wednesday) Next(ctx *DayContext) {
ctx.today = &Thursday{}
}
type Thursday struct{}
func (*Thursday) Today() {
fmt.Printf("Thursday\n")
}
func (*Thursday) Next(ctx *DayContext) {
ctx.today = &Friday{}
}
type Friday struct{}
func (*Friday) Today() {
fmt.Printf("Friday\n")
}
func (*Friday) Next(ctx *DayContext) {
ctx.today = &Saturday{}
}
type Saturday struct{}
func (*Saturday) Today() {
fmt.Printf("Saturday\n")
}
func (*Saturday) Next(ctx *DayContext) {
ctx.today = &Sunday{}
}