live_cells::cell_state Class Reference

Maintains the state of a stateful cell. More...

#include <cell_state.hpp>

Inheritance diagram for live_cells::cell_state:

Collaboration diagram for live_cells::cell_state:

Public Types
typedef std::shared_ptr< cell_state >	ref
	Shared pointer to a cell_state.

Public Member Functions
	cell_state (key_ref k)
	Create a cell state with a given key.
cell_state &	operator= (const cell_state &other)=delete
virtual void	init ()
	Called before the first observer is added.
virtual void	pause ()
	Called after the last observer is removed.
virtual void	add_observer (observer::ref o)
	Add an observer to the cell's set of observers.
virtual void	remove_observer (observer::ref o)
	Remove an observer from the cell's set of observers.
virtual void	notify_will_update ()
	Notify the observers that the cell's value will change.
virtual void	notify_update (bool did_change=true)
	Notify the observers that the cell's value has changed.

Protected Member Functions
bool	is_active () const
	Does the cell have at least one observer?

Protected Attributes
key_ref	key_
	Key identifying the cell corresponding to this state.
std::unordered_map< observer::ref, std::size_t >	observers
	The set of observers observing changes to the values in the cell corresponding to this state.

Detailed Description

Maintains the state of a stateful cell.

The state consists of the cell's observers and its value. The base class provides functionality for keeping track of observers added to the cell.

This object is intended to be held in an std::shared_ptr with a single instance per unique cell key. Multiple cell objects with same key reference the same cell_state.

A state is created when the first stateful cell with a given key is created, and is destroyed when the last cell with the given key is destroyed.

Constructor & Destructor Documentation

cell_state()

live_cells::cell_state::cell_state ( key_ref k )

inline

Create a cell state with a given key.

Parameters

k

The key

Member Function Documentation

add_observer()

void live_cells::cell_state::add_observer ( observer::ref o )

virtual

Add an observer to the cell's set of observers.

Parameters

o	The observer to add

init()

virtual void live_cells::cell_state::init ( )

inlinevirtual

Called before the first observer is added.

Subclasses should override this method to include initialization logic specific to this cell state.

Note

If the state needs to set up observers to other cells, it should be done in this method.

Reimplemented in live_cells::compute_cell_state< C >, live_cells::compute_cell_state< dynamic_compute_state< F > >, live_cells::compute_cell_state< store_cell_compute_state< C > >, live_cells::dynamic_compute_cell_state< F >, live_cells::mutable_compute_cell_state< T >, live_cells::mutable_compute_cell_state< std::invoke_result_t< F > >, live_cells::peek_cell_state< C >, live_cells::previous_value_cell_state< C >, and live_cells::store_cell_state< C >.

is_active()

bool live_cells::cell_state::is_active ( ) const

inlineprotected

Does the cell have at least one observer?

Returns

true if the cell has at least one observer.

notify_update()

void live_cells::cell_state::notify_update ( bool did_change = true )

virtual

Notify the observers that the cell's value has changed.

This should be called after the value has been changed.

Parameters

did_change

True if the value of the cell may have changed, false if it is known that the value of the cell has not changed.

notify_will_update()

void live_cells::cell_state::notify_will_update ( )

virtual

Notify the observers that the cell's value will change.

This should be called before the value is changed.

pause()

virtual void live_cells::cell_state::pause ( )

inlinevirtual

Called after the last observer is removed.

Subclasses should override this method to include cleanup logic specific to this cell state.

Note

Observers added in init() should be removed in this method.

Reimplemented in live_cells::compute_cell_state< C >, live_cells::compute_cell_state< dynamic_compute_state< F > >, live_cells::compute_cell_state< store_cell_compute_state< C > >, live_cells::dynamic_compute_cell_state< F >, live_cells::mutable_compute_cell_state< T >, live_cells::mutable_compute_cell_state< std::invoke_result_t< F > >, live_cells::peek_cell_state< C >, live_cells::previous_value_cell_state< C >, and live_cells::store_cell_state< C >.

remove_observer()

void live_cells::cell_state::remove_observer ( observer::ref o )

virtual

Remove an observer from the cell's set of observers.

Like the remove_observer method of the Cell concept, this method should be called the same number of times, for a given observer o, as add_observer() was called, before the observer is actually removed.

Parameters

o	The observer to remove

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

• src/cell_state.hpp
• src/live_cells.cpp