Go fsm

package fsm  import (     "log" )  type EvtIf interface {     GetEvtType() string }  type Action interface {     //doAction(evt EvtIf, srcState *State, dstState *State)     doAction(evt EvtIf) }  type Transition struct {     dstState *State     action   Action }  type State struct {     name          string     isEnd         bool     transitionTbl map[string]Transition }  type fsm struct {     InstId        uint64     version       uint32     startPoint    *State     current       *State     transitionLog []Transition     stateTbl      map[string]*State }  //func StartStateMachine(transtionLog []Transition) *fsm { //} //func ReplyStateMachine(transtionLog []Transition) *fsm { //} //func Save() *fsm { //} //func Load() *fms { //}  func NewState(name string, end bool) *State {     return &State{name, end, map[string]Transition{}} }  func (this *State) GetName() string {     return this.name }  func (this *State) InterestInEvt(evt EvtIf) bool {     if evt == nil {         return false     }     _, exists := this.transitionTbl[evt.GetEvtType()]     return exists }  func (this *State) AddTransition(evt EvtIf, dst *State, action Action) {     if evt == nil || dst == nil || action == nil {         log.Fatal("AddTransition error, parameter invalid!")     }     _, exists := this.transitionTbl[evt.GetEvtType()]     if exists {         log.Fatal("AddTransition error,EvtIf exist")     }     this.transitionTbl[evt.GetEvtType()] = NewTransition(dst, action) }  func (this *State) GetTransition(evt EvtIf) *Transition {     if evt == nil {         return nil     }      tran, exists := this.transitionTbl[evt.GetEvtType()]     if exists == false {         log.Fatal("GetTransition error,EvtIf doesn't exist")     }     return &tran }  func NewTransition(dstState *State, action Action) Transition {     return Transition{dstState, action} }  func (this *fsm) RegisterState(state *State) {     if state == nil {         log.Fatal("RegisterState error, parameter invalid!")     }     _, exists := this.stateTbl[state.GetName()]     if exists {         return         log.Fatal("RegisterState error,State exist")     }     this.stateTbl[state.GetName()] = state }  func (this *fsm) AddTransition(srcState *State, evt EvtIf, dstState *State, action Action) {     if srcState == nil || dstState == nil || evt == nil || action == nil {         log.Fatal("AddTransition error, parameter invalid!")     }     this.RegisterState(srcState)     this.RegisterState(dstState)     srcState.AddTransition(evt, dstState, action) }  func (this *fsm) AddInternalTransition(srcState *State, evt EvtIf, action Action) {     this.AddTransition(srcState, evt, srcState, action) }  func (this *fsm) HandleEvt(evt EvtIf) {     if evt == nil {         return     }      srcState := this.current     if srcState.InterestInEvt(evt) {         transition := srcState.GetTransition(evt)         log.Printf("Handle Event, srcState:%s, dstState:%s, evt:%s", srcState.GetName(), transition.dstState.GetName(), evt.GetEvtType())         //transition.action.doAction(evt, srcState, transition.dstState)         transition.action.doAction(evt)         this.current = transition.dstState     } else {         log.Printf("parameter invalid, srcState:%s, evt:%s", srcState.GetName(), evt.GetEvtType())     } }  func NewFsm(initialState *State) *fsm {     if initialState == nil {         log.Fatal("NewFsm error, parameter invalid!")     }     return &fsm{initialState, map[string]*State{}} }