add a very simple fsm

fsm/fsm.go

@@ -0,0 +1,92 @@
+package fsm
+
+type Stater interface {
+	Enter()
+	Exit()
+	CheckTransition(event int) bool
+}
+
+type FSM struct {
+	// 持有状态集合
+	states map[string]Stater
+	// 当前状态
+	currentState Stater
+	// 默认状态
+	defaultState Stater
+	// 外部输入数据
+	inputData int
+	// 是否初始化
+	inited bool
+}
+
+// 重置
+func (this *FSM) Reset() {
+	this.inited = false
+}
+
+// 初始化FSM
+func (this *FSM) Init() {
+	this.Reset()
+}
+
+// 添加状态到FSM
+func (this *FSM) AddState(key string, state Stater) {
+	if this.states == nil {
+		this.states = make(map[string]Stater, 2)
+	}
+	this.states[key] = state
+}
+
+// 设置默认的State
+func (this *FSM) SetDefaultState(state Stater) {
+	this.defaultState = state
+}
+
+// 转移状态
+func (this *FSM) TransitionState() {
+	inputData := this.inputData
+	/*
+		nextState := this.defaultState
+		if this.inited {
+			for _, v := range this.states {
+				if v.Can(inputData) {
+					nextState = v
+					break
+				}
+			}
+		}
+	*/
+	if !this.inited {
+		this.currentState = this.defaultState
+	}
+
+	for _, next := range this.states {
+		if next.CheckTransition(inputData) {
+			if this.currentState != nil {
+				this.currentState.Exit()
+			}
+			this.currentState = next
+			this.inited = true
+			next.Enter()
+			break
+		}
+	}
+
+	/*
+		if ok := nextState.CheckTransition(inputData); ok {
+			if this.currentState != nil {
+				// 退出前一个状态
+				this.currentState.Exit()
+			}
+			this.currentState = nextState
+			this.inited = true
+			nextState.Enter()
+		}
+	*/
+}
+
+// 输入数据
+func (this *FSM) InputData(inputData int) {
+	this.inputData = inputData
+	this.TransitionState()
+}

fsm/fsm_test.go

@@ -0,0 +1,54 @@
+package fsm
+
+import (
+	"log"
+	"testing"
+)
+
+const (
+	RUNNING = iota
+	STOPPED
+)
+
+type RunningState int
+
+func (s *RunningState) Enter() {
+	log.Println("enter running state")
+}
+
+func (s *RunningState) Exit() {
+	log.Println("out of running")
+}
+
+func (s *RunningState) CheckTransition(ev int) bool {
+	return ev == RUNNING
+}
+
+type StoppedState int
+
+func (s *StoppedState) Enter() {
+	log.Println("Stopped enter")
+}
+
+func (s *StoppedState) Exit() {
+	log.Println("Stopped exit")
+}
+
+func (s *StoppedState) CheckTransition(ev int) bool {
+	return ev == STOPPED
+}
+
+func TestFSM(t *testing.T) {
+	t.Log("Hello")
+	rstate := new(RunningState)
+	sstate := new(StoppedState)
+
+	fsm := new(FSM)
+	fsm.AddState("running", rstate)
+	fsm.AddState("stopped", sstate)
+	//fsm.SetDefaultState(sstate)
+	fsm.Init()
+	fsm.InputData(RUNNING)
+	fsm.InputData(STOPPED)
+	fsm.InputData(RUNNING)
+}