Base class for entities that track a typed state value with change-detection and callbacks. More...

#include <entity_base.h>

Inheritance diagram for esphome::StatefulEntityBase< T >:

Public Member Functions
virtual const T &	get_state () const =0
	Return the current state value. Only valid when has_state() is true.

T	get_state_default (T default_value) const
	Return the current state if available, otherwise return the provided default.

void	invalidate_state ()
	Clear the state — sets has_state() to false and fires callbacks with nullopt.

template<typename F >
void	add_full_state_callback (F &&callback)

template<typename F >
void	add_on_state_callback (F &&callback)

Public Member Functions inherited from esphome::EntityBase
	ESPDEPRECATED ("Use get_name_to() or get_log_name() instead. Will be removed in ESPHome 2027.5.0", "2026.11.0") const StringRef &get_name() const
	The name is in flash here; the first call makes a RAM copy that is kept for the life of the device.

StringRef	get_name_to (std::span< char, ENTITY_NAME_BUF_SIZE > buffer) const
	Get the name of this Entity, copied out of flash into buffer.

	ESPDEPRECATED ("Use get_name_to() or get_log_name() instead. Will be removed in ESPHome 2027.5.0", "2026.11.0") const StringRef &get_name() const

const StringRef &	get_name_to (std::span< char, ENTITY_NAME_BUF_SIZE >) const

bool	name_equals (const StringRef &other) const

const ProgmemStringRef &	get_name_progmem () const
	The name as stored, for consumers that read flash themselves (e.g. API progmem fields).

size_t	write_name_to (char *buf, size_t buf_size) const
	Copy the name into buf (null terminated), returns its length.

const LogString *	get_log_name () const
	Get the name for a "%s" log argument (LOG_STR_ARG).

bool	has_own_name () const

uint32_t	get_object_id_hash () const

StringRef	get_object_id_to (std::span< char, OBJECT_ID_MAX_LEN > buf) const
	Get object_id with zero heap allocation For static case: returns StringRef to internal storage (buffer unused) For dynamic case: formats into buffer and returns StringRef to buffer.

size_t	write_object_id_to (char *buf, size_t buf_size) const
	Write object_id directly to buffer, returns length written (excluding null) Useful for building compound strings without intermediate buffer.

bool	is_internal () const

void	set_internal (bool internal)

bool	is_disabled_by_default () const

EntityCategory	get_entity_category () const

const char *	get_device_class_to (std::span< char, MAX_DEVICE_CLASS_LENGTH > buffer) const

ProgmemStringRef	get_device_class_progmem () const
	The device class as stored (in flash on ESP8266), for consumers that read flash themselves.

StringRef	get_unit_of_measurement_ref () const

const char *	get_icon_to (std::span< char, MAX_ICON_LENGTH > buffer) const

ProgmemStringRef	get_icon_progmem () const
	The icon as stored (in flash on ESP8266), for consumers that read flash themselves.

uint32_t	get_device_id () const

Device *	get_device () const

bool	has_state () const

void	set_has_state (bool state)

	ESPDEPRECATED ("Use make_entity_preference<T>() instead, or preferences won't be migrated. " "See https://github.com/esphome/backlog/issues/85. Will be removed in 2027.1.0.", "2026.7.0") uint32_t get_preference_hash()
	Get a unique hash for storing preferences/settings for this entity.

template<typename T >
ESPPreferenceObject	make_entity_preference (uint32_t version=0)
	Create a preference object for storing this entity's state/settings.

template<typename T >
ESPPreferenceObject	make_entity_preference (uint32_t version, bool in_flash)
	As make_entity_preference(), stored in flash or RTC memory where the backend supports the choice.

Protected Member Functions
virtual bool	get_trigger_on_initial_state () const =0
	Subclasses return whether callbacks should fire on the very first state.

virtual bool	set_new_state (const optional< T > &new_state)
	Apply a new state, de-duplicating and firing callbacks as needed.

virtual void	set_state_value (const T &value)=0
	Subclasses implement this to store the actual value into their own storage.

Protected Member Functions inherited from esphome::EntityBase
friend	void::setup ()

friend	void::original_setup ()

void	configure_entity_ (const char *name, uint32_t object_id_hash, uint32_t entity_fields)
	Combined entity setup from codegen: set name, object_id hash, entity string indices, and flags.

void	set_device_ (Device *device)

ESPPreferenceObject	make_entity_preference_ (size_t size, uint32_t version)
	Non-template helpers for make_entity_preference() to avoid code bloat.

ESPPreferenceObject	make_entity_preference_ (size_t size, uint32_t version, bool in_flash)

uint32_t	entity_preference_key_ (uint32_t version)
	Key for both helpers; preference hash migration goes here.

Protected Attributes
LazyCallbackManager< void(optional< T > previous, optional< T > current)>	full_state_callbacks_

LazyCallbackManager< void(T)>	state_callbacks_

Protected Attributes inherited from esphome::EntityBase
ProgmemStringRef	name_

uint32_t	object_id_hash_ {}

Device *	device_ {}

struct esphome::EntityBase::EntityFlags	flags_

uint8_t	device_class_idx_ {}

uint8_t	uom_idx_ {}

uint8_t	icon_idx_ {}

Detailed Description

template<typename T>
class esphome::StatefulEntityBase< T >

Base class for entities that track a typed state value with change-detection and callbacks.

This class does not store the state value — subclasses own their storage. Whether a state has been set is tracked by EntityBase::has_state().

Subclasses must implement:

get_state(): return a const reference to the current value
set_state_value(): store a new value (called only when the state actually changes)
get_trigger_on_initial_state(): return whether callbacks should fire on the first state

Subclasses may override set_new_state() to add behavior (logging, notifications) after calling the base implementation. Since set_new_state() is virtual, callers like invalidate_state() dispatch through the vtable to the subclass override in the .cpp, avoiding template code bloat at inline call sites. Subclasses may also add a fast-path dedup check before calling set_new_state() to skip virtual dispatch entirely when the state hasn't changed.

Callback behavior:

full_state_callbacks_: fired on every change, receives optional<T> previous and current
state_callbacks_: fired only when the new state has a value, and either this is not the first state (had_state) or trigger_on_initial_state is set

Template Parameters

T	The type of the state value

Definition at line 322 of file entity_base.h.

Member Function Documentation

◆ add_full_state_callback()

template<typename T >

template<typename F >

void esphome::StatefulEntityBase< T >::add_full_state_callback ( F && callback )

inline

Definition at line 331 of file entity_base.h.

◆ add_on_state_callback()

template<typename T >

template<typename F >

void esphome::StatefulEntityBase< T >::add_on_state_callback ( F && callback )

inline

Definition at line 334 of file entity_base.h.

◆ get_state()

template<typename T >

virtual const T & esphome::StatefulEntityBase< T >::get_state ( ) const

pure virtual

Return the current state value. Only valid when has_state() is true.

Implemented in esphome::binary_sensor::BinarySensor.

◆ get_state_default()

template<typename T >

T esphome::StatefulEntityBase< T >::get_state_default ( T default_value ) const

inline

Return the current state if available, otherwise return the provided default.

Definition at line 327 of file entity_base.h.

◆ get_trigger_on_initial_state()

template<typename T >

virtual bool esphome::StatefulEntityBase< T >::get_trigger_on_initial_state ( ) const

protectedpure virtual

Subclasses return whether callbacks should fire on the very first state.

Implemented in esphome::binary_sensor::BinarySensor.

◆ invalidate_state()

template<typename T >

void esphome::StatefulEntityBase< T >::invalidate_state ( )

inline

Clear the state — sets has_state() to false and fires callbacks with nullopt.

Definition at line 329 of file entity_base.h.

◆ set_new_state()

template<typename T >

virtual bool esphome::StatefulEntityBase< T >::set_new_state ( const optional< T > & new_state )

inlineprotectedvirtual

Apply a new state, de-duplicating and firing callbacks as needed.

Pass nullopt to invalidate (clear) the state. Pass a value to set it. Returns true if the state actually changed, false if it was the same. Subclasses may override to add logging/notifications after calling the base.

Reimplemented in esphome::binary_sensor::BinarySensor.

Definition at line 348 of file entity_base.h.

◆ set_state_value()

template<typename T >

virtual void esphome::StatefulEntityBase< T >::set_state_value ( const T & value )

protectedpure virtual

Subclasses implement this to store the actual value into their own storage.

Implemented in esphome::binary_sensor::BinarySensor.

Field Documentation

◆ full_state_callbacks_

template<typename T >

LazyCallbackManager<void(optional<T> previous, optional<T> current)> esphome::StatefulEntityBase< T >::full_state_callbacks_

protected

Definition at line 378 of file entity_base.h.

◆ state_callbacks_

template<typename T >

LazyCallbackManager<void(T)> esphome::StatefulEntityBase< T >::state_callbacks_

protected

Definition at line 379 of file entity_base.h.

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

esphome/core/entity_base.h

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Member Function Documentation

◆ add_full_state_callback()

◆ add_on_state_callback()

◆ get_state()

◆ get_state_default()

◆ get_trigger_on_initial_state()

◆ invalidate_state()

◆ set_new_state()

◆ set_state_value()

Field Documentation

◆ full_state_callbacks_

◆ state_callbacks_