LcmBuses Class Reference

Detailed Description

A mapping from {bus_name: interface} with sugar for error checking with nice error messages during access.

Note that this class is shallow-const. A user of a const LcmBuses object cannot add or remove buses, but can retrieve a non-const DrakeLcmInterface pointer and then "modify" the object it points to by subscribing to a channel.

#include <drake/systems/lcm/lcm_buses.h>

Public Member Functions
	LcmBuses ()
	Constructs an empty mapping. More...
	~LcmBuses ()
int	size () const
	Returns the total number of buses. More...
drake::lcm::DrakeLcmInterface *	Find (std::string_view description_of_caller, const std::string &bus_name) const
	Finds the bus of the given name, or throws if there is no such bus. More...
std::vector< std::string_view >	GetAllBusNames () const
	Returns a list of all known bus_name keys. More...
void	Add (std::string bus_name, drake::lcm::DrakeLcmInterface *)
	Adds a bus. More...
Implements CopyConstructible, CopyAssignable, MoveConstructible, MoveAssignable
	LcmBuses (const LcmBuses &)=default
LcmBuses &	operator= (const LcmBuses &)=default
	LcmBuses (LcmBuses &&)=default
LcmBuses &	operator= (LcmBuses &&)=default

Static Public Attributes
static constexpr char	kLcmUrlMemqNull [] = "memq://null"
	A magic LCM URL sentinel value for the "null" LCM interface. More...

Constructor & Destructor Documentation

LcmBuses() [1/3]

LcmBuses ( const LcmBuses &  )

default

LcmBuses() [2/3]

LcmBuses ( LcmBuses &&  )

default

LcmBuses() [3/3]

LcmBuses

(

)

Constructs an empty mapping.

~LcmBuses()

~LcmBuses

(

)

Member Function Documentation

Add()

void Add	(	std::string	bus_name,
		drake::lcm::DrakeLcmInterface *
	)

Adds a bus.

Throws if the bus is nullptr, or if there was already a bus of the same name.

Find()

drake::lcm::DrakeLcmInterface* Find	(	std::string_view	description_of_caller,
		const std::string &	bus_name
	)		const

Finds the bus of the given name, or throws if there is no such bus.

The return value is an alias into memory owned elsewhere (typically by a DiagramBuilder or a Diagram) and is never nullptr.

Parameters

description_of_caller

is a noun phrase that will be used when creating an error message. A typical value would be something like "Camera 5", "Robot controller", "The default visualizer", or etc.

GetAllBusNames()

std::vector<std::string_view> GetAllBusNames

(

)

const

Returns a list of all known bus_name keys.

operator=() [1/2]

LcmBuses& operator= ( LcmBuses &&  )

default

operator=() [2/2]

LcmBuses& operator= ( const LcmBuses &  )

default

size()

int size

(

)

const

Returns the total number of buses.

Member Data Documentation

kLcmUrlMemqNull

constexpr char kLcmUrlMemqNull[] = "memq://null"

static

A magic LCM URL sentinel value for the "null" LCM interface.

In some cases, LCM messages are unwanted but we need to pass around a well-formed DrakeLcmParams or DrakeLcmInterface object. Instead of passing nullptr objects, instead we pass an object set to use this URL. For example, this URL is used when ApplyLcmBusConfig() is given a nullopt DrakeLcmParams. The expectation is that interfaces with this URL will not even be pumped (i.e., no calls to HandleSubscriptions).

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

• drake/systems/lcm/lcm_buses.h