#include <networktables/Topic.h>

Inheritance diagram for nt::Topic:

Public Member Functions
	Topic ()=default

	Topic (NT_Topic handle)

	operator bool () const
	Determines if the native handle is valid. More...

NT_Topic	GetHandle () const
	Gets the native handle for the topic. More...

NetworkTableInstance	GetInstance () const
	Gets the instance for the topic. More...

std::string	GetName () const
	Gets the name of the topic. More...

NetworkTableType	GetType () const
	Gets the type of the topic. More...

std::string	GetTypeString () const
	Gets the type string of the topic. More...

void	SetPersistent (bool persistent)
	Make value persistent through server restarts. More...

bool	IsPersistent () const
	Returns whether the value is persistent through server restarts. More...

void	SetRetained (bool retained)
	Make the server retain the topic even when there are no publishers. More...

bool	IsRetained () const
	Returns whether the topic is retained by server when there are no publishers. More...

void	SetCached (bool cached)
	Allow storage of the topic's last value, allowing the value to be read (and not just accessed through event queues and listeners). More...

bool	IsCached () const
	Returns whether the topic's last value is stored. More...

bool	Exists () const
	Determines if the topic is currently being published. More...

wpi::json	GetProperty (std::string_view name) const
	Gets the current value of a property (as a JSON object). More...

void	SetProperty (std::string_view name, const wpi::json &value)
	Sets a property value. More...

void	DeleteProperty (std::string_view name)
	Deletes a property. More...

wpi::json	GetProperties () const
	Gets all topic properties as a JSON object. More...

bool	SetProperties (const wpi::json &properties)
	Updates multiple topic properties. More...

TopicInfo	GetInfo () const
	Gets combined information about the topic. More...

GenericSubscriber	GenericSubscribe (const PubSubOptions &options=kDefaultPubSubOptions)
	Create a new subscriber to the topic. More...

GenericSubscriber	GenericSubscribe (std::string_view typeString, const PubSubOptions &options=kDefaultPubSubOptions)
	Create a new subscriber to the topic. More...

GenericPublisher	GenericPublish (std::string_view typeString, const PubSubOptions &options=kDefaultPubSubOptions)
	Create a new publisher to the topic. More...

GenericPublisher	GenericPublishEx (std::string_view typeString, const wpi::json &properties, const PubSubOptions &options=kDefaultPubSubOptions)
	Create a new publisher to the topic, with type string and initial properties. More...

GenericEntry	GetGenericEntry (const PubSubOptions &options=kDefaultPubSubOptions)
	Create a new generic entry for the topic. More...

GenericEntry	GetGenericEntry (std::string_view typeString, const PubSubOptions &options=kDefaultPubSubOptions)
	Create a new generic entry for the topic. More...

bool	operator== (const Topic &) const =default
	Equality operator. More...

Protected Attributes
NT_Topic	m_handle {0}

Detailed Description

NetworkTables Topic.

Constructor & Destructor Documentation

◆ Topic() [1/2]

nt::Topic::Topic ( )

default

◆ Topic() [2/2]

nt::Topic::Topic ( NT_Topic handle )

inlineexplicit

Member Function Documentation

◆ DeleteProperty()

void nt::Topic::DeleteProperty ( std::string_view name )

inline

Deletes a property.

Has no effect if the property does not exist.

Parameters

name	property name

◆ Exists()

bool nt::Topic::Exists ( ) const

inline

Determines if the topic is currently being published.

Returns: True if the topic exists, false otherwise.

◆ GenericPublish()

GenericPublisher nt::Topic::GenericPublish	(	std::string_view	typeString,
		const PubSubOptions &	options = `kDefaultPubSubOptions`
	)

Create a new publisher to the topic.

The publisher is only active as long as the returned object is not destroyed.

Note: It is not possible to publish two different data types to the same topic. Conflicts between publishers are typically resolved by the server on a first-come, first-served basis. Any published values that do not match the topic's data type are dropped (ignored). To determine if the data type matches, use the appropriate Topic functions.

Parameters

typeString	type string
options	publish options

Returns: publisher

◆ GenericPublishEx()

GenericPublisher nt::Topic::GenericPublishEx	(	std::string_view	typeString,
		const wpi::json &	properties,
		const PubSubOptions &	options = `kDefaultPubSubOptions`
	)

Create a new publisher to the topic, with type string and initial properties.

The publisher is only active as long as the returned object is not destroyed.

Note: It is not possible to publish two different data types to the same topic. Conflicts between publishers are typically resolved by the server on a first-come, first-served basis. Any published values that do not match the topic's data type are dropped (ignored). To determine if the data type matches, use the appropriate Topic functions.

Parameters

typeString	type string
properties	JSON properties
options	publish options

Returns: publisher

◆ GenericSubscribe() [1/2]

GenericSubscriber nt::Topic::GenericSubscribe ( const PubSubOptions & options = kDefaultPubSubOptions )

Create a new subscriber to the topic.

The subscriber is only active as long as the returned object is not destroyed.

Parameters

options subscribe options

Returns: subscriber

◆ GenericSubscribe() [2/2]

GenericSubscriber nt::Topic::GenericSubscribe	(	std::string_view	typeString,
		const PubSubOptions &	options = `kDefaultPubSubOptions`
	)

Create a new subscriber to the topic.

The subscriber is only active as long as the returned object is not destroyed.

Note: Subscribers that do not match the published data type do not return any values. To determine if the data type matches, use the appropriate Topic functions.

Parameters

typeString	type string
options	subscribe options

Returns: subscriber

◆ GetGenericEntry() [1/2]

GenericEntry nt::Topic::GetGenericEntry ( const PubSubOptions & options = kDefaultPubSubOptions )

Create a new generic entry for the topic.

Entries act as a combination of a subscriber and a weak publisher. The subscriber is active as long as the entry is not destroyed. The publisher is created when the entry is first written to, and remains active until either Unpublish() is called or the entry is destroyed.

Note: It is not possible to use two different data types with the same topic. Conflicts between publishers are typically resolved by the server on a first-come, first-served basis. Any published values that do not match the topic's data type are dropped (ignored), and the entry will show no new values if the data type does not match. To determine if the data type matches, use the appropriate Topic functions.

Parameters

options publish and/or subscribe options

Returns: entry

◆ GetGenericEntry() [2/2]

GenericEntry nt::Topic::GetGenericEntry	(	std::string_view	typeString,
		const PubSubOptions &	options = `kDefaultPubSubOptions`
	)

Create a new generic entry for the topic.

Entries act as a combination of a subscriber and a weak publisher. The subscriber is active as long as the entry is not destroyed. The publisher is created when the entry is first written to, and remains active until either Unpublish() is called or the entry is destroyed.

Note: It is not possible to use two different data types with the same topic. Conflicts between publishers are typically resolved by the server on a first-come, first-served basis. Any published values that do not match the topic's data type are dropped (ignored), and the entry will show no new values if the data type does not match. To determine if the data type matches, use the appropriate Topic functions.

Parameters

typeString	type string
options	publish and/or subscribe options

Returns: entry

◆ GetHandle()

NT_Topic nt::Topic::GetHandle ( ) const

inline

Gets the native handle for the topic.

Returns: Native handle

◆ GetInfo()

TopicInfo nt::Topic::GetInfo ( ) const

inline

Gets combined information about the topic.

Returns: Topic information

◆ GetInstance()

NetworkTableInstance nt::Topic::GetInstance ( ) const

Gets the instance for the topic.

Returns: Instance

◆ GetName()

std::string nt::Topic::GetName ( ) const

inline

Gets the name of the topic.

Returns: the topic's name

◆ GetProperties()

wpi::json nt::Topic::GetProperties ( ) const

Gets all topic properties as a JSON object.

Each key in the object is the property name, and the corresponding value is the property value.

Returns: JSON object

◆ GetProperty()

wpi::json nt::Topic::GetProperty ( std::string_view name ) const

Gets the current value of a property (as a JSON object).

Parameters

name	property name

Returns: JSON object; null object if the property does not exist.

◆ GetType()

NetworkTableType nt::Topic::GetType ( ) const

inline

Gets the type of the topic.

Returns: the topic's type

◆ GetTypeString()

std::string nt::Topic::GetTypeString ( ) const

inline

Gets the type string of the topic.

This may have more information than the numeric type (especially for raw values).

Returns: the topic's type

◆ IsCached()

bool nt::Topic::IsCached ( ) const

inline

Returns whether the topic's last value is stored.

Returns: True if the topic is cached.

◆ IsPersistent()

bool nt::Topic::IsPersistent ( ) const

inline

Returns whether the value is persistent through server restarts.

Returns: True if the value is persistent.

◆ IsRetained()

bool nt::Topic::IsRetained ( ) const

inline

Returns whether the topic is retained by server when there are no publishers.

Returns: True if the topic is retained.

◆ operator bool()

nt::Topic::operator bool ( ) const

inlineexplicit

Determines if the native handle is valid.

Returns: True if the native handle is valid, false otherwise.

◆ operator==()

bool nt::Topic::operator== ( const Topic & ) const

default

Equality operator.

Returns true if both instances refer to the same native handle.

◆ SetCached()

void nt::Topic::SetCached ( bool cached )

inline

Allow storage of the topic's last value, allowing the value to be read (and not just accessed through event queues and listeners).

Parameters

cached True for cached, false for not cached.

◆ SetPersistent()

void nt::Topic::SetPersistent ( bool persistent )

inline

Make value persistent through server restarts.

Parameters

persistent True for persistent, false for not persistent.

◆ SetProperties()

bool nt::Topic::SetProperties ( const wpi::json & properties )

inline

Updates multiple topic properties.

Each key in the passed-in object is the name of the property to add/update, and the corresponding value is the property value to set for that property. Null values result in deletion of the corresponding property.

Parameters

properties JSON object with keys to add/update/delete

Returns: False if properties is not an object

◆ SetProperty()

void nt::Topic::SetProperty	(	std::string_view	name,
		const wpi::json &	value
	)

Sets a property value.

Parameters

name	property name
value	property value

◆ SetRetained()

void nt::Topic::SetRetained ( bool retained )

inline

Make the server retain the topic even when there are no publishers.

Parameters

retained True for retained, false for not retained.

Member Data Documentation

◆ m_handle

NT_Topic nt::Topic::m_handle {0}

protected

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

networktables/Topic.h
networktables/Topic.inc

Public Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Topic() [1/2]

◆ Topic() [2/2]

Member Function Documentation

◆ DeleteProperty()

◆ Exists()

◆ GenericPublish()

◆ GenericPublishEx()

◆ GenericSubscribe() [1/2]

◆ GenericSubscribe() [2/2]

◆ GetGenericEntry() [1/2]

◆ GetGenericEntry() [2/2]

◆ GetHandle()

◆ GetInfo()

◆ GetInstance()

◆ GetName()

◆ GetProperties()

◆ GetProperty()

◆ GetType()

◆ GetTypeString()

◆ IsCached()

◆ IsPersistent()

◆ IsRetained()

◆ operator bool()

◆ operator==()

◆ SetCached()

◆ SetPersistent()

◆ SetProperties()

◆ SetProperty()

◆ SetRetained()

Member Data Documentation

◆ m_handle