NetworkTables unit-typed topic. More...

#include <networktables/UnitTopic.h>

Inheritance diagram for nt::UnitTopic< T >:

Public Types
using	SubscriberType = UnitSubscriber< T >

using	PublisherType = UnitPublisher< T >

using	EntryType = UnitEntry< T >

using	ValueType = T

using	ParamType = T

using	TimestampedValueType = TimestampedUnit< T >

Public Member Functions
	UnitTopic ()=default

	UnitTopic (NT_Topic handle)
	Construct from a topic handle. More...

	UnitTopic (Topic topic)
	Construct from a generic topic. More...

bool	IsMatchingUnit () const
	Verify the topic has a matching unit type (if the topic is published). More...

SubscriberType	Subscribe (ParamType defaultValue, const PubSubOptions &options=kDefaultPubSubOptions)
	Create a new subscriber to the topic. More...

SubscriberType	SubscribeEx (std::string_view typeString, ParamType defaultValue, const PubSubOptions &options=kDefaultPubSubOptions)
	Create a new subscriber to the topic, with specific type string. More...

PublisherType	Publish (const PubSubOptions &options=kDefaultPubSubOptions)
	Create a new publisher to the topic. More...

PublisherType	PublishEx (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...

EntryType	GetEntry (ParamType defaultValue, const PubSubOptions &options=kDefaultPubSubOptions)
	Create a new entry for the topic. More...

EntryType	GetEntryEx (std::string_view typeString, ParamType defaultValue, const PubSubOptions &options=kDefaultPubSubOptions)
	Create a new entry for the topic, with specific type string. More...

Public Member Functions inherited from nt::Topic
	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...

Static Public Attributes
static constexpr std::string_view	kTypeString = "double"
	The default type string for this topic type. More...

Additional Inherited Members
Protected Attributes inherited from nt::Topic
NT_Topic	m_handle {0}

Detailed Description

template<typename T>
class nt::UnitTopic< T >

NetworkTables unit-typed topic.

Publishers publish the type name (e.g. "meter") as the "unit" property. Type conversions are not performed–for correct behavior the publisher and subscriber must use the same unit type, but this can be checked at runtime using IsMatchingUnit().

Template Parameters

T	unit type, e.g. units::meter_t

Member Typedef Documentation

◆ EntryType

template<typename T >

using nt::UnitTopic< T >::EntryType = UnitEntry<T>

◆ ParamType

template<typename T >

using nt::UnitTopic< T >::ParamType = T

◆ PublisherType

template<typename T >

using nt::UnitTopic< T >::PublisherType = UnitPublisher<T>

◆ SubscriberType

template<typename T >

using nt::UnitTopic< T >::SubscriberType = UnitSubscriber<T>

◆ TimestampedValueType

template<typename T >

using nt::UnitTopic< T >::TimestampedValueType = TimestampedUnit<T>

◆ ValueType

template<typename T >

using nt::UnitTopic< T >::ValueType = T

Constructor & Destructor Documentation

◆ UnitTopic() [1/3]

template<typename T >

nt::UnitTopic< T >::UnitTopic ( )

default

◆ UnitTopic() [2/3]

template<typename T >

nt::UnitTopic< T >::UnitTopic ( NT_Topic handle )

inlineexplicit

Construct from a topic handle.

Parameters

handle Native handle

◆ UnitTopic() [3/3]

template<typename T >

nt::UnitTopic< T >::UnitTopic ( Topic topic )

inlineexplicit

Construct from a generic topic.

Parameters

topic Topic

Member Function Documentation

◆ GetEntry()

template<typename T >

UnitEntry< T > nt::UnitTopic< T >::GetEntry	(	ParamType	defaultValue,
		const PubSubOptions &	options = `kDefaultPubSubOptions`
	)

inline

Create a new 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

defaultValue	default value used when a default is not provided to a getter function
options	publish and/or subscribe options

Returns: entry

◆ GetEntryEx()

template<typename T >

UnitEntry< T > nt::UnitTopic< T >::GetEntryEx	(	std::string_view	typeString,
		ParamType	defaultValue,
		const PubSubOptions &	options = `kDefaultPubSubOptions`
	)

inline

Create a new entry for the topic, with specific type string.

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
defaultValue	default value used when a default is not provided to a getter function
options	publish and/or subscribe options

Returns: entry

◆ IsMatchingUnit()

template<typename T >

bool nt::UnitTopic< T >::IsMatchingUnit

inline

Verify the topic has a matching unit type (if the topic is published).

Returns: True if unit matches, false if not matching or topic not published.

◆ Publish()

template<typename T >

UnitPublisher< T > nt::UnitTopic< T >::Publish ( const PubSubOptions & options = kDefaultPubSubOptions )

inline

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

options publish options

Returns: publisher

◆ PublishEx()

template<typename T >

UnitPublisher< T > nt::UnitTopic< T >::PublishEx	(	std::string_view	typeString,
		const wpi::json &	properties,
		const PubSubOptions &	options = `kDefaultPubSubOptions`
	)

inline

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

◆ Subscribe()

template<typename T >

UnitSubscriber< T > nt::UnitTopic< T >::Subscribe	(	ParamType	defaultValue,
		const PubSubOptions &	options = `kDefaultPubSubOptions`
	)

inline

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

defaultValue	default value used when a default is not provided to a getter function
options	subscribe options

Returns: subscriber

◆ SubscribeEx()

template<typename T >

UnitSubscriber< T > nt::UnitTopic< T >::SubscribeEx	(	std::string_view	typeString,
		ParamType	defaultValue,
		const PubSubOptions &	options = `kDefaultPubSubOptions`
	)

inline

Create a new subscriber to the topic, with specific type string.

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
defaultValue	default value used when a default is not provided to a getter function
options	subscribe options

Returns: subscriber

Member Data Documentation

◆ kTypeString

template<typename T >

constexpr std::string_view nt::UnitTopic< T >::kTypeString = "double"

staticconstexpr

The default type string for this topic type.

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

networktables/UnitTopic.h
networktables/UnitTopic.inc

Public Types

Public Member Functions

Static Public Attributes

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ EntryType

◆ ParamType

◆ PublisherType

◆ SubscriberType

◆ TimestampedValueType

◆ ValueType

Constructor & Destructor Documentation

◆ UnitTopic() [1/3]

◆ UnitTopic() [2/3]

◆ UnitTopic() [3/3]

Member Function Documentation

◆ GetEntry()

◆ GetEntryEx()

◆ IsMatchingUnit()

◆ Publish()

◆ PublishEx()

◆ Subscribe()

◆ SubscribeEx()

Member Data Documentation

◆ kTypeString