Acts::NavigationPolicyState Class Reference

Wrapper class for a navigation policy state stored in the state manager. More...

#include <Acts/Navigation/INavigationPolicy.hpp>

Public Member Functions
template<typename T>
T &	as ()
	Cast the state to a specific type.
template<typename T>
const T &	as () const
	Cast the state to a specific type (const version).
NavigationPolicyState	atIndex (std::size_t index) const
	Access another state managed by the same manager, by absolute stack index.
bool	empty () const
	Check if the state is empty (not associated with a manager).
std::size_t	index () const
	Absolute index of this state within its manager's state stack.
bool	isDefault () const
	Whether this state is the default sentinel, i.e.

Detailed Description

Wrapper class for a navigation policy state stored in the state manager.

This class provides type-safe access to the underlying state through the as<T>() method. The state is stored as a type-erased, small-buffer optimized value (NavigationPolicyStateStorage) in the NavigationPolicyStateManager.

Member Function Documentation

as() [1/2]

template<typename T>

T & Acts::NavigationPolicyState::as

(

)

Cast the state to a specific type.

Template Parameters

T	The type to cast to

Returns

Reference to the state as type T

as() [2/2]

template<typename T>

const T & Acts::NavigationPolicyState::as

(

)

const

Cast the state to a specific type (const version).

Template Parameters

T	The type to cast to

Returns

Const reference to the state as type T

atIndex()

NavigationPolicyState Acts::NavigationPolicyState::atIndex

(

std::size_t

index

)

const

Access another state managed by the same manager, by absolute stack index.

Composite policies use this to reach their child states, which are pushed contiguously onto the stack directly below the composite's own state.

Parameters

index

absolute stack index of the state to access

Returns

wrapper for the state at index in the same manager

empty()

bool Acts::NavigationPolicyState::empty

(

)

const

Check if the state is empty (not associated with a manager).

Returns

True if the state is empty, false otherwise

index()

std::size_t Acts::NavigationPolicyState::index

(

)

const

Absolute index of this state within its manager's state stack.

Returns

the stack index

isDefault()

bool Acts::NavigationPolicyState::isDefault

(

)

const

Whether this state is the default sentinel, i.e.

either no state at all or the INavigationPolicy::EmptyState pushed by policies that do not override createState(). Such policies also use the default (always-true) isValid(), so the navigator treats a default state as "no validity constraint" and skips the per-step isValid() call. A policy with a meaningful isValid() necessarily pushes a real state to check against, so this signal cannot be forgotten.

Returns

True if this is the default/empty state