Merge pull request #8 from textnow/add-base-state

Refactored State into InternalState and ExternalState

base_state.go

@@ -0,0 +1,61 @@
+package hsm
+
+import (
+	"fmt"
+	"go.uber.org/zap"
+)
+
+// BaseState implements the InternalState interface
+type BaseState struct {
+	name        string
+	parentState State
+	logger      *zap.Logger
+	entered     bool
+	exited      bool
+}
+
+// NewBaseState constructor
+func NewBaseState(name string, parentState State, logger *zap.Logger) *BaseState {
+	return &BaseState{
+		name:        name,
+		parentState: parentState,
+		logger:      logger,
+	}
+}
+
+// Name getter
+func (b *BaseState) Name() string {
+	return b.name
+}
+
+// ParentState getter
+func (b *BaseState) ParentState() State {
+	return b.parentState
+}
+
+// Entered getter
+func (b *BaseState) Entered() bool {
+	return b.entered
+}
+
+// Exited getter
+func (b *BaseState) Exited() bool {
+	return b.exited
+}
+
+// Logger getter
+func (b *BaseState) Logger() *zap.Logger {
+	return b.logger
+}
+
+// VerifyNotEntered makes sure that this state is only entered once
+func (b *BaseState) VerifyNotEntered() {
+	Precondition(b.logger, !b.entered, fmt.Sprintf("State %s has already been entered", b.name))
+	b.entered = true
+}
+
+// VerifyNotExited make sure that this state is only exited once
+func (b *BaseState) VerifyNotExited() {
+	Precondition(b.logger, !b.exited, fmt.Sprintf("State %s has already been exited", b.name))
+	b.exited = true
+}

base_state_test.go

@@ -0,0 +1,36 @@
+package hsm
+
+import (
+	"github.com/stretchr/testify/assert"
+	"go.uber.org/zap/zaptest"
+	"testing"
+)
+
+func TestNewBaseState(t *testing.T) {
+	logger := zaptest.NewLogger(t)
+	baseState := NewBaseState("baseStateName", nil, logger)
+
+	assert.Equal(t, "baseStateName", baseState.Name())
+	assert.Nil(t, baseState.ParentState())
+	assert.False(t, baseState.Entered())
+	assert.False(t, baseState.Exited())
+	assert.Equal(t, logger, baseState.Logger())
+}
+
+func TestBaseState_VerifyNotEntered(t *testing.T) {
+	logger := zaptest.NewLogger(t)
+	baseState := NewBaseState("baseStateName", nil, logger)
+
+	assert.False(t, baseState.Entered())
+	baseState.VerifyNotEntered()
+	assert.True(t, baseState.Entered())
+}
+
+func TestBaseState_VerifyNotExited(t *testing.T) {
+	logger := zaptest.NewLogger(t)
+	baseState := NewBaseState("baseStateName", nil, logger)
+
+	assert.False(t, baseState.Exited())
+	baseState.VerifyNotExited()
+	assert.True(t, baseState.Exited())
+}

example/samek/states/state_s0.go

@@ -1,70 +1,42 @@
 package states
 
 import (
-	"fmt"
 	"github.com/Enflick/gohsm"
 	"go.uber.org/zap"
 )
 
 // S0State represents State S0
 type S0State struct {
-	logger  *zap.Logger
-	entered bool
-	exited  bool
+	hsm.BaseState
 }
 
 // NewS0State constructor
 func NewS0State(logger *zap.Logger) *S0State {
 	return &S0State{
-		logger: logger,
+		BaseState: *hsm.NewBaseState("S0", nil, logger),
 	}
 }
 
-// Name returns the state's name
-func (s *S0State) Name() string {
-	return "S0"
-}
-
 // OnEnter enters this state
 func (s *S0State) OnEnter(event hsm.Event) hsm.State {
-	hsm.Precondition(s.logger, !s.entered, fmt.Sprintf("State %s has already been entered", s.Name()))
-	s.logger.Debug("->S0;")
-	s.entered = true
-
-	stateS1 := NewS1State(s.logger, s)
-
-	return stateS1.OnEnter(event)
+	s.VerifyNotEntered()
+	s.Logger().Debug("->S0;")
+	return NewS1State(s.Logger(), s).OnEnter(event)
 }
 
 // OnExit enters this state
 func (s *S0State) OnExit(event hsm.Event) hsm.State {
-	hsm.Precondition(s.logger, !s.exited, fmt.Sprintf("State %s has already been exited", s.Name()))
-	s.logger.Debug("<-S0;")
-	s.exited = true
+	s.VerifyNotExited()
+	s.Logger().Debug("<-S0;")
 	return s.ParentState()
 }
 
 // EventHandler returns a transition associated with the event or NilTransition if the event is not handled
 func (s *S0State) EventHandler(event hsm.Event) hsm.Transition {
 	switch event.ID() {
 	case ee.ID():
-		return hsm.NewExternalTransition(event, NewS2State(s.logger, s), hsm.NopAction)
+		return hsm.NewExternalTransition(event, NewS2State(s.Logger(), s), hsm.NopAction)
 	default:
-		return hsm.NilTransition
+		return nil
 	}
 }
-
-// ParentState returns the parentState or NilState
-func (s *S0State) ParentState() hsm.State {
-	return hsm.NilState
-}
-
-// Entered returns true if this state have been entered
-func (s *S0State) Entered() bool {
-	return s.entered
-}
-
-// Exited returns true if this state have been exited
-func (s *S0State) Exited() bool {
-	return s.exited
-}

example/samek/states/state_s1.go

@@ -8,77 +8,48 @@ import (
 
 // S1State represents State S1
 type S1State struct {
-	logger      *zap.Logger
-	parentState *S0State
-	entered     bool
-	exited      bool
+	hsm.BaseState
 }
 
 // NewS1State constructor
-func NewS1State(logger *zap.Logger, parentState *S0State) *S1State {
+func NewS1State(logger *zap.Logger, parentState hsm.State) *S1State {
 	hsm.Precondition(logger, parentState != nil, fmt.Sprintf("NewS1State: parentState cannot be nil"))
 
 	state := &S1State{
-		logger:      logger,
-		parentState: parentState,
+		BaseState: *hsm.NewBaseState("S1", parentState, logger),
 	}
 
 	return state
 }
 
-// Name returns the state's name
-func (s *S1State) Name() string {
-	return "S1"
-}
-
 // OnEnter enters this state
 func (s *S1State) OnEnter(event hsm.Event) hsm.State {
-	hsm.Precondition(s.logger, !s.entered, fmt.Sprintf("State %s has already been entered", s.Name()))
-	s.logger.Debug("->S1;")
-	s.entered = true
-
-	stateS1 := NewS11State(s.logger, s)
-
-	return stateS1.OnEnter(event)
+	s.VerifyNotEntered()
+	s.Logger().Debug("->S1;")
+	return NewS11State(s.Logger(), s).OnEnter(event)
 }
 
 // OnExit enters this state
 func (s *S1State) OnExit(event hsm.Event) hsm.State {
-	hsm.Precondition(s.logger, !s.exited, fmt.Sprintf("State %s has already been exited", s.Name()))
-	s.logger.Debug("<-S1;")
-	s.exited = true
+	s.VerifyNotExited()
+	s.Logger().Debug("<-S1;")
 	return s.ParentState()
 }
 
 // EventHandler returns a transition associated with the event or NilTransition if the event is not handled
 func (s *S1State) EventHandler(event hsm.Event) hsm.Transition {
 	switch event.ID() {
 	case ea.ID():
-		return hsm.NewExternalTransition(event, NewS1State(s.logger, s.parentState), hsm.NopAction)
+		return hsm.NewExternalTransition(event, NewS1State(s.Logger(), s.ParentState()), hsm.NopAction)
 	case eb.ID():
-		return hsm.NewExternalTransition(event, NewS11State(s.logger, s), hsm.NopAction)
+		return hsm.NewExternalTransition(event, NewS11State(s.Logger(), s), hsm.NopAction)
 	case ec.ID():
-		return hsm.NewExternalTransition(event, NewS2State(s.logger, s.parentState), hsm.NopAction)
+		return hsm.NewExternalTransition(event, NewS2State(s.Logger(), s.ParentState()), hsm.NopAction)
 	case ed.ID():
-		return hsm.NewExternalTransition(event, NewS0State(s.logger), hsm.NopAction)
+		return hsm.NewExternalTransition(event, NewS0State(s.Logger()), hsm.NopAction)
 	case ef.ID():
-		return hsm.NewExternalTransition(event, NewS2State(s.logger, s.parentState), hsm.NopAction)
+		return hsm.NewExternalTransition(event, NewS2State(s.Logger(), s.ParentState()), hsm.NopAction)
 	default:
-		return hsm.NilTransition
+		return nil
 	}
 }
-
-// ParentState returns the parentState or NilState
-func (s *S1State) ParentState() hsm.State {
-	return s.parentState
-}
-
-// Entered returns true if this state have been entered
-func (s *S1State) Entered() bool {
-	return s.entered
-}
-
-// Exited returns true if this state have been exited
-func (s *S1State) Exited() bool {
-	return s.exited
-}

example/samek/states/state_s11.go

@@ -8,66 +8,40 @@ import (
 
 // S11State represents State S11
 type S11State struct {
-	logger      *zap.Logger
-	parentState *S1State
-	entered     bool
-	exited      bool
+	hsm.BaseState
 }
 
 // NewS11State constructor
 func NewS11State(logger *zap.Logger, parentState *S1State) *S11State {
 	hsm.Precondition(logger, parentState != nil, fmt.Sprintf("NewS11State: parentState cannot be nil"))
 
 	state := &S11State{
-		logger:      logger,
-		parentState: parentState,
+		BaseState: *hsm.NewBaseState("S11", parentState, logger),
 	}
 
 	return state
 }
 
-// Name returns the state's name
-func (s *S11State) Name() string {
-	return "S11"
-}
-
 // OnEnter enters this state
 func (s *S11State) OnEnter(event hsm.Event) hsm.State {
-	hsm.Precondition(s.logger, !s.entered, fmt.Sprintf("State %s has already been entered", s.Name()))
-	s.logger.Debug("->S11;")
-	s.entered = true
+	s.VerifyNotEntered()
+	s.Logger().Debug("->S11;")
 	return s
 }
 
 // OnExit enters this state
 func (s *S11State) OnExit(event hsm.Event) hsm.State {
-	hsm.Precondition(s.logger, !s.exited, fmt.Sprintf("State %s has already been exited", s.Name()))
-	s.logger.Debug("<-S11;")
-	s.exited = true
+	s.VerifyNotExited()
+	s.Logger().Debug("<-S11;")
 	return s.ParentState()
 }
 
 // EventHandler returns a transition associated with the event or NilTransition if the event is not handled
 func (s *S11State) EventHandler(event hsm.Event) hsm.Transition {
 	switch event.ID() {
 	case eg.ID():
-		return hsm.NewExternalTransition(event, NewS2State(s.logger, s.parentState.parentState), hsm.NopAction)
+		return hsm.NewExternalTransition(event, NewS2State(s.Logger(), s.ParentState().ParentState()), hsm.NopAction)
 	default:
-		return hsm.NilTransition
+		return nil
 	}
 }
-
-// ParentState returns the parentState or NilState
-func (s *S11State) ParentState() hsm.State {
-	return s.parentState
-}
-
-// Entered returns true if this state have been entered
-func (s *S11State) Entered() bool {
-	return s.entered
-}
-
-// Exited returns true if this state have been exited
-func (s *S11State) Exited() bool {
-	return s.exited
-}