StateManager Class Template

Manages state transitions using a rule-based system. More...

Declaration

template <typename StateType> class helios::engine::state::StateManager<StateType> { ... }

Base classes

class	Manager
	Abstract base class for managers that process deferred operations. More...
class	TypedStateCommandHandler<StateType>
	Typed interface for handling state commands. More...

Public Constructors Index

template <typename StateType>
StateManager (std::span< const StateTransitionRule< StateType > > rules)
	Constructs a state manager with transition rules. More...

Public Member Functions Index

template <typename StateType>
StateManager &	addStateListener (std::unique_ptr< StateTransitionListener< StateType > > listener) noexcept
	Registers a state transition listener. More...
template <typename StateType>
void	flush (helios::engine::runtime::world::GameWorld &gameWorld, helios::engine::runtime::world::UpdateContext &updateContext) noexcept override
	Processes pending state commands. More...
template <typename StateType>
bool	submit (const StateCommand< StateType > &stateCommand) noexcept override
	Submits a state command for processing. More...
template <typename StateType>
void	init (helios::engine::runtime::world::GameWorld &gameWorld) override
	Initializes the manager and registers with GameWorld. More...
template <typename StateType>
void	reset () override
	Clears all pending commands. More...

Private Member Functions Index

template <typename StateType>
void	signalExit (const StateType from, const StateType to, const StateTransitionIdType< StateType > transitionId, helios::engine::runtime::world::UpdateContext &updateContext)
	Notifies listeners of state exit. More...
template <typename StateType>
void	signalTransition (const StateType from, const StateType to, const StateTransitionIdType< StateType > transitionId, helios::engine::runtime::world::UpdateContext &updateContext)
	Notifies listeners of the transition. More...
template <typename StateType>
void	signalEnter (const StateType from, const StateType to, const StateTransitionIdType< StateType > transitionId, helios::engine::runtime::world::UpdateContext &updateContext)
	Notifies listeners of state entry. More...

Private Member Attributes Index

template <typename StateType>
std::vector< StateCommand< StateType > >	pending_
	Queue of pending state commands. More...
template <typename StateType>
std::vector< std::unique_ptr< StateTransitionListener< StateType > > >	listeners_
	Registered transition listeners. More...
template <typename StateType>
std::vector< StateTransitionRule< StateType > >	rules_
	Transition rules defining valid state changes. More...

Description

Manages state transitions using a rule-based system.

Implements both Manager and TypedStateCommandHandler interfaces. Processes state transition commands by matching against registered rules, executing guards, and notifying listeners.

## Transition Flow

1. Commands are submitted via submit() and queued 2. During flush(), the last pending command is processed 3. Rules are checked to find a matching transition 4. If a guard is present, it must return true 5. Listeners are notified: onStateExit -> onStateTransition -> onStateEnter 6. Session state is updated

Template Parameters

StateType

The state enum type.

See Also

StateTransitionRule

See Also

StateTransitionListener

See Also

StateCommand

Definition at line 64 of file StateManager.ixx.

Public Constructors

StateManager()

template <typename StateType>

helios::engine::state::StateManager< StateType >::StateManager (std::span< const StateTransitionRule< StateType > > rules)

inline explicit

Constructs a state manager with transition rules.

Parameters

rules

Span of valid transition rules.

Definition at line 151 of file StateManager.ixx.

151 explicit StateManager(std::span<const StateTransitionRule<StateType>> rules)

152 : rules_(rules.begin(), rules.end()) {}

Public Member Functions

addStateListener()

template <typename StateType>

StateManager & helios::engine::state::StateManager< StateType >::addStateListener (std::unique_ptr< StateTransitionListener< StateType > > listener)

inline noexcept

Registers a state transition listener.

Parameters

listener

The listener to add.

Returns

Reference to this manager for chaining.

Definition at line 161 of file StateManager.ixx.

161 StateManager& addStateListener(std::unique_ptr<StateTransitionListener<StateType>> listener) noexcept {

162 listeners_.push_back(std::move(listener));

163 return *this;

164 }

flush()

template <typename StateType>

void helios::engine::state::StateManager< StateType >::flush (helios::engine::runtime::world::GameWorld & gameWorld, helios::engine::runtime::world::UpdateContext & updateContext)

inline noexcept virtual

Processes pending state commands.

Processes the last pending command, finds matching rules, executes guards, and triggers the transition if valid.

Parameters

gameWorld	The game world.
updateContext	The current frame's update context.

Definition at line 175 of file StateManager.ixx.

175 void flush(

176 helios::engine::runtime::world::GameWorld& gameWorld,

177 helios::engine::runtime::world::UpdateContext& updateContext

178 ) noexcept override {

179

180 if (pending_.empty()) {

181 return;

182 }

183

184 auto command = pending_.back();

185

186 auto transitionRequest = command.transitionRequest();

187

188 auto& session = gameWorld.session();

189 auto currentFrom = session.state<StateType>();

190 auto from = transitionRequest.from();

191 auto transitionId = transitionRequest.transitionId();

192

193

194 if (currentFrom != from) {

195 pending_.clear();

196 return;

197 }

198

199

200 for (auto& rule : rules_) {

201 if (rule.from() == from && rule.transitionId() == transitionId) {

202

203 if (rule.guard()) {

204 if (!rule.guard()(updateContext, transitionRequest)) {

205 break;

206 }

207 }

208

209 signalExit(from, rule.to(), transitionId, updateContext);

210 signalTransition(from, rule.to(), transitionId, updateContext);

211 session.setStateFrom<StateType>(StateTransitionContext<StateType>{rule.from(), rule.to(), transitionId});

212 signalEnter(from, rule.to(), transitionId, updateContext);

213 }

214 }

215

216 pending_.clear();

217 }

init()

template <typename StateType>

void helios::engine::state::StateManager< StateType >::init (helios::engine::runtime::world::GameWorld & gameWorld)

inline virtual

Initializes the manager and registers with GameWorld.

Parameters

gameWorld

The game world to register with.

Definition at line 238 of file StateManager.ixx.

238 void init(helios::engine::runtime::world::GameWorld& gameWorld) override {

239 gameWorld.registerStateCommandHandler<StateType>(*this);

240 }

reset()

template <typename StateType>

void helios::engine::state::StateManager< StateType >::reset ()

inline virtual

Clears all pending commands.

Definition at line 245 of file StateManager.ixx.

245 void reset() override {

246 pending_.clear();

247 }

submit()

template <typename StateType>

bool helios::engine::state::StateManager< StateType >::submit (const StateCommand< StateType > & stateCommand)

inline noexcept virtual

Submits a state command for processing.

Parameters

stateCommand

The command to queue.

Returns

True (always accepts commands).

Definition at line 226 of file StateManager.ixx.

226 bool submit(

227 const StateCommand<StateType>& stateCommand

228 ) noexcept override {

229 pending_.push_back(stateCommand);

230 return true;

231 };

Private Member Functions

signalEnter()

template <typename StateType>

void helios::engine::state::StateManager< StateType >::signalEnter (const StateType from, const StateType to, const StateTransitionIdType< StateType > transitionId, helios::engine::runtime::world::UpdateContext & updateContext)

inline

Notifies listeners of state entry.

Parameters

from	The source state.
to	The state being entered.
transitionId	The transition identifier.
updateContext	The current frame's update context.

Definition at line 131 of file StateManager.ixx.

131 void signalEnter(

132 const StateType from,

133 const StateType to,

134 const StateTransitionIdType<StateType> transitionId,

135 helios::engine::runtime::world::UpdateContext& updateContext) {

136

137 for (auto& listener : listeners_) {

138 listener->onStateEnter(updateContext, to);

139

140 }

141 }

signalExit()

template <typename StateType>

void helios::engine::state::StateManager< StateType >::signalExit (const StateType from, const StateType to, const StateTransitionIdType< StateType > transitionId, helios::engine::runtime::world::UpdateContext & updateContext)

inline

Notifies listeners of state exit.

Parameters

from	The state being exited.
to	The target state.
transitionId	The transition identifier.
updateContext	The current frame's update context.

Definition at line 90 of file StateManager.ixx.

90 void signalExit(

91 const StateType from,

92 const StateType to,

93 const StateTransitionIdType<StateType> transitionId,

94 helios::engine::runtime::world::UpdateContext& updateContext) {

95

96 for (auto& listener : listeners_) {

97 listener->onStateExit(updateContext, from);

98 }

99 }

signalTransition()

template <typename StateType>

void helios::engine::state::StateManager< StateType >::signalTransition (const StateType from, const StateType to, const StateTransitionIdType< StateType > transitionId, helios::engine::runtime::world::UpdateContext & updateContext)

inline

Notifies listeners of the transition.

Parameters

from	The source state.
to	The target state.
transitionId	The transition identifier.
updateContext	The current frame's update context.

Definition at line 109 of file StateManager.ixx.

109 void signalTransition(

110 const StateType from,

111 const StateType to,

112 const StateTransitionIdType<StateType> transitionId,

113 helios::engine::runtime::world::UpdateContext& updateContext) {

114

115 for (auto& listener : listeners_) {

116 listener->onStateTransition(

117 updateContext,

118 StateTransitionContext<StateType>{from, to, transitionId}

119 );

120 }

121 }

Private Member Attributes

listeners_

template <typename StateType>

std::vector<std::unique_ptr<StateTransitionListener<StateType> > > helios::engine::state::StateManager< StateType >::listeners_

Registered transition listeners.

Definition at line 75 of file StateManager.ixx.

75 std::vector<std::unique_ptr<StateTransitionListener<StateType>>> listeners_;

pending_

template <typename StateType>

std::vector<StateCommand<StateType> > helios::engine::state::StateManager< StateType >::pending_

Queue of pending state commands.

Definition at line 70 of file StateManager.ixx.

70 std::vector<StateCommand<StateType>> pending_;

rules_

template <typename StateType>

std::vector<StateTransitionRule<StateType> > helios::engine::state::StateManager< StateType >::rules_

Transition rules defining valid state changes.

Definition at line 80 of file StateManager.ixx.

80 std::vector<StateTransitionRule<StateType>> rules_;

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The documentation for this class was generated from the following file:

• StateManager.ixx

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