The main class for ROS topic subscription, message timeout handling etc. More...

#include <subscribe_handler.h>

Classes
class	Impl

class	ImplThreadsafe

Public Types
using	message_type = MessageType
	Convenience type for the template parameter to enable nice aliasing.

using	timeout_callback_t = std::function< void(const std::string &topic_name, const ros::Time &last_msg)>
	Type for the timeout callback function.

using	message_callback_t = std::function< void(typename MessageType::ConstPtr)>
	Convenience type for the message callback function.

Public Member Functions
virtual MessageType::ConstPtr	getMsg ()
	Returns the last received message on the topic, handled by this SubscribeHandler. Use hasMsg() first to check if at least one message is available or newMsg() to check if a new message since the last call to getMsg() is available. More...

virtual MessageType::ConstPtr	peekMsg () const
	Returns the last received message on the topic without modifying the newMsg() or usedMsg() flags. More...

virtual bool	hasMsg () const
	Used to check whether at least one message has been received on the handled topic. More...

virtual bool	newMsg () const
	Used to check whether at least one message has been received on the handled topic since the last call to getMsg(). More...

virtual bool	usedMsg () const
	Used to check whether getMsg() was called at least once on this SubscribeHandler. More...

virtual MessageType::ConstPtr	waitForNew (const ros::WallDuration &timeout)
	Blocks until new data becomes available or until the timeout runs out or until a spurious wake-up. More...

virtual ros::Time	lastMsgTime () const
	Returns time of the last received message on the topic, handled by this SubscribeHandler. More...

virtual std::string	topicName () const
	Returns the resolved (full) name of the topic, handled by this SubscribeHandler. More...

virtual std::string	subscribedTopicName () const
	Returns the subscribed (unresolved) name of the topic, handled by this SubscribeHandler. More...

virtual uint32_t	getNumPublishers () const
	Returns number of publishers registered at the topic. More...

virtual void	setNoMessageTimeout (const ros::Duration &timeout)
	Sets the timeout for no received message. More...

virtual void	start ()
	Enables the callbacks for the handled topic. More...

virtual void	stop ()
	Disables the callbacks for the handled topic. More...

	SubscribeHandler ()
	Default constructor to avoid having to use pointers. More...

template<class ... Types>
	SubscribeHandler (const SubscribeHandlerOptions &options, const std::string &topic_name, Types ... args)
	Main constructor. More...

	SubscribeHandler (const SubscribeHandlerOptions &options, const message_callback_t &message_callback={})
	Convenience constructor overload. More...

template<class ... Types>
	SubscribeHandler (const SubscribeHandlerOptions &options, const timeout_callback_t &timeout_callback, Types ... args)
	Convenience constructor overload. More...

template<class ObjectType1 , class ... Types>
	SubscribeHandler (const SubscribeHandlerOptions &options, void(ObjectType1::const timeout_callback)(const std::string &topic_name, const ros::Time &last_msg), ObjectType1 const obj1, Types ... args)
	Convenience constructor overload. More...

template<class ObjectType2 , class ... Types>
	SubscribeHandler (const SubscribeHandlerOptions &options, void(ObjectType2::const message_callback)(typename MessageType::ConstPtr), ObjectType2 const obj2, Types ... args)
	Convenience constructor overload. More...

template<class ObjectType1 , class ObjectType2 , class ... Types>
	SubscribeHandler (const SubscribeHandlerOptions &options, void(ObjectType2::const message_callback)(typename MessageType::ConstPtr), ObjectType2 const obj2, void(ObjectType1::const timeout_callback)(const std::string &topic_name, const ros::Time &last_msg), ObjectType1 const obj1, Types ... args)
	Convenience constructor overload. More...

template<class ... Types>
	SubscribeHandler (const SubscribeHandlerOptions &options, const ros::Duration &no_message_timeout, Types ... args)
	Convenience constructor overload. More...

template<class ... Types>
	SubscribeHandler (const SubscribeHandlerOptions &options, mrs_lib::TimeoutManager &timeout_manager, Types ... args)
	Convenience constructor overload. More...

	SubscribeHandler (const SubscribeHandler &)=delete

SubscribeHandler &	operator= (const SubscribeHandler &)=delete

	SubscribeHandler (SubscribeHandler &&other)

SubscribeHandler &	operator= (SubscribeHandler &&other)

Detailed Description

template<typename MessageType>
class mrs_lib::SubscribeHandler< MessageType >

The main class for ROS topic subscription, message timeout handling etc.

This class handles the raw ROS Subscriber for a specified topic. The last message received on the topic is remembered and may be retrieved by calling the getMsg() method. To check whether at least one message was received, use hasMsg() (if no message was received and you call getMsg(), a nullptr is returned and an error message is printed). To check whether a new message has arrived since the last call to getMsg(), use newMsg() (useful to check whether a new message needs to be processed in a loop or ROS Timer callback).

A timeout callback function may be specified, which is called if no message is received on the topic for a specified timeout (use the timeout_callback and no_message_timeout parameters). If the timeout callback is not set by the user, an error message is printed to the console after the timeout by default.

A message callback function may be specified, which is called whenever a new message is received (use the message_callback parameter).

The callbacks and timeouts may be stopped and started using the stop() and start() methods.

For more details, see the example below (I recommend starting with the simple_example which covers most use-cases).

Examples: subscribe_handler/example.cpp, and subscribe_handler/simple_example.cpp.

Constructor & Destructor Documentation

◆ SubscribeHandler() [1/9]

template<typename MessageType >

mrs_lib::SubscribeHandler< MessageType >::SubscribeHandler ( )

inline

Default constructor to avoid having to use pointers.

It does nothing and the SubscribeHandler it constructs will also do nothing. Use some of the other constructors for actual construction of a usable SubscribeHandler.

◆ SubscribeHandler() [2/9]

template<typename MessageType >

template<class ... Types>

mrs_lib::SubscribeHandler< MessageType >::SubscribeHandler	(	const SubscribeHandlerOptions &	options,
		const std::string &	topic_name,
		Types ...	args
	)

inline

Main constructor.

Parameters

options	The common options struct (see documentation of SubscribeHandlerOptions).
topic_name	Name of the topic to be handled by this subscribed.
args	Remaining arguments to be parsed (see other constructors).

◆ SubscribeHandler() [3/9]

template<typename MessageType >

mrs_lib::SubscribeHandler< MessageType >::SubscribeHandler	(	const SubscribeHandlerOptions &	options,
		const message_callback_t &	message_callback = `{}`
	)

inline

Convenience constructor overload.

Parameters

options	The common options struct (see documentation of SubscribeHandlerOptions).
message_callback	The callback function to call when a new message is received (you can leave this argument empty and just use the newMsg()/hasMsg() and getMsg() interface).

◆ SubscribeHandler() [4/9]

template<typename MessageType >

template<class ... Types>

mrs_lib::SubscribeHandler< MessageType >::SubscribeHandler	(	const SubscribeHandlerOptions &	options,
		const timeout_callback_t &	timeout_callback,
		Types ...	args
	)

inline

Convenience constructor overload.

Parameters

options	The common options struct (see documentation of SubscribeHandlerOptions).
timeout_callback	The callback function to call when a new message is not received for the duration, specified in `options` or in the `no_message_timeout` parameter.
args	Remaining arguments to be parsed (see other constructors).

◆ SubscribeHandler() [5/9]

template<typename MessageType >

template<class ObjectType1 , class ... Types>

mrs_lib::SubscribeHandler< MessageType >::SubscribeHandler	(	const SubscribeHandlerOptions &	options,
		void(ObjectType1::*)(const std::string &topic_name, const ros::Time &last_msg)	timeout_callback,
		ObjectType1 *const	obj1,
		Types ...	args
	)

inline

Convenience constructor overload.

Parameters

options	The common options struct (see documentation of SubscribeHandlerOptions).
timeout_callback	The callback method to call when a new message is not received for the duration, specified in `options` or in the `no_message_timeout` parameter.
obj1	The object on which the callback method `timeout_callback` will be called.
args	Remaining arguments to be parsed (see other constructors).

◆ SubscribeHandler() [6/9]

template<typename MessageType >

template<class ObjectType2 , class ... Types>

mrs_lib::SubscribeHandler< MessageType >::SubscribeHandler	(	const SubscribeHandlerOptions &	options,
		void(ObjectType2::*)(typename MessageType::ConstPtr)	message_callback,
		ObjectType2 *const	obj2,
		Types ...	args
	)

inline

Convenience constructor overload.

Parameters

options	The common options struct (see documentation of SubscribeHandlerOptions).
message_callback	The callback method to call when a new message is received.
obj2	The object on which the callback method `timeout_callback` will be called.
args	Remaining arguments to be parsed (see other constructors).

◆ SubscribeHandler() [7/9]

template<typename MessageType >

template<class ObjectType1 , class ObjectType2 , class ... Types>

mrs_lib::SubscribeHandler< MessageType >::SubscribeHandler	(	const SubscribeHandlerOptions &	options,
		void(ObjectType2::*)(typename MessageType::ConstPtr)	message_callback,
		ObjectType2 *const	obj2,
		void(ObjectType1::*)(const std::string &topic_name, const ros::Time &last_msg)	timeout_callback,
		ObjectType1 *const	obj1,
		Types ...	args
	)

inline

Convenience constructor overload.

Parameters

options	The common options struct (see documentation of SubscribeHandlerOptions).
message_callback	The callback method to call when a new message is received.
obj2	The object on which the callback method `timeout_callback` will be called.
timeout_callback	The callback method to call when a new message is not received for the duration, specified in `options` or in the `no_message_timeout` parameter.
obj1	The object on which the callback method `timeout_callback` will be called.
args	Remaining arguments to be parsed (see other constructors).

◆ SubscribeHandler() [8/9]

template<typename MessageType >

template<class ... Types>

mrs_lib::SubscribeHandler< MessageType >::SubscribeHandler	(	const SubscribeHandlerOptions &	options,
		const ros::Duration &	no_message_timeout,
		Types ...	args
	)

inline

Convenience constructor overload.

Parameters

options	The common options struct (see documentation of SubscribeHandlerOptions).
no_message_timeout	If no message is received for this duration, the timeout callback function is called. If no timeout callback is specified, an error message is printed to the console.
args	Remaining arguments to be parsed (see other constructors).

◆ SubscribeHandler() [9/9]

template<typename MessageType >

template<class ... Types>

mrs_lib::SubscribeHandler< MessageType >::SubscribeHandler	(	const SubscribeHandlerOptions &	options,
		mrs_lib::TimeoutManager &	timeout_manager,
		Types ...	args
	)

inline

Convenience constructor overload.

Parameters

options	The common options struct (see documentation of SubscribeHandlerOptions).
timeout_manager	The manager for timeout callbacks.
args	Remaining arguments to be parsed (see other constructors).

Member Function Documentation

◆ getMsg()

template<typename MessageType >

virtual MessageType::ConstPtr mrs_lib::SubscribeHandler< MessageType >::getMsg ( )

inlinevirtual

Returns the last received message on the topic, handled by this SubscribeHandler. Use hasMsg() first to check if at least one message is available or newMsg() to check if a new message since the last call to getMsg() is available.

Returns: the last received message.

◆ getNumPublishers()

template<typename MessageType >

virtual uint32_t mrs_lib::SubscribeHandler< MessageType >::getNumPublishers ( ) const

inlinevirtual

Returns number of publishers registered at the topic.

Returns: number of publishers.

◆ hasMsg()

template<typename MessageType >

virtual bool mrs_lib::SubscribeHandler< MessageType >::hasMsg ( ) const

inlinevirtual

Used to check whether at least one message has been received on the handled topic.

Returns: true if at least one message was received, otherwise false.

◆ lastMsgTime()

template<typename MessageType >

virtual ros::Time mrs_lib::SubscribeHandler< MessageType >::lastMsgTime ( ) const

inlinevirtual

Returns time of the last received message on the topic, handled by this SubscribeHandler.

Returns: time when the last message was received.

◆ newMsg()

template<typename MessageType >

virtual bool mrs_lib::SubscribeHandler< MessageType >::newMsg ( ) const

inlinevirtual

Used to check whether at least one message has been received on the handled topic since the last call to getMsg().

Returns: true if at least one message was received, otherwise false.

◆ peekMsg()

template<typename MessageType >

virtual MessageType::ConstPtr mrs_lib::SubscribeHandler< MessageType >::peekMsg ( ) const

inlinevirtual

Returns the last received message on the topic without modifying the newMsg() or usedMsg() flags.

Returns: the last received message.

◆ setNoMessageTimeout()

template<typename MessageType >

virtual void mrs_lib::SubscribeHandler< MessageType >::setNoMessageTimeout ( const ros::Duration & timeout )

inlinevirtual

Sets the timeout for no received message.

Parameters

timeout The new timeout for no received messages.

◆ start()

template<typename MessageType >

virtual void mrs_lib::SubscribeHandler< MessageType >::start ( )

inlinevirtual

Enables the callbacks for the handled topic.

If the SubscribeHandler object is stopped using the stop() method, no callbacks will be called until the start() method is called.

◆ stop()

template<typename MessageType >

virtual void mrs_lib::SubscribeHandler< MessageType >::stop ( )

inlinevirtual

Disables the callbacks for the handled topic.

All messages after this method is called will be ignored until start() is called again. Timeout checking will also be disabled.

◆ subscribedTopicName()

template<typename MessageType >

virtual std::string mrs_lib::SubscribeHandler< MessageType >::subscribedTopicName ( ) const

inlinevirtual

Returns the subscribed (unresolved) name of the topic, handled by this SubscribeHandler.

Returns: name of the handled topic.

◆ topicName()

template<typename MessageType >

virtual std::string mrs_lib::SubscribeHandler< MessageType >::topicName ( ) const

inlinevirtual

Returns the resolved (full) name of the topic, handled by this SubscribeHandler.

Returns: name of the handled topic.

◆ usedMsg()

template<typename MessageType >

virtual bool mrs_lib::SubscribeHandler< MessageType >::usedMsg ( ) const

inlinevirtual

Used to check whether getMsg() was called at least once on this SubscribeHandler.

Returns: true if getMsg() was called at least once, otherwise false.

◆ waitForNew()

template<typename MessageType >

virtual MessageType::ConstPtr mrs_lib::SubscribeHandler< MessageType >::waitForNew ( const ros::WallDuration & timeout )

inlinevirtual

Blocks until new data becomes available or until the timeout runs out or until a spurious wake-up.

Parameters

timeout after this duration, this method will return a nullptr if no new data becomes available.

Returns: the message if a new message is available after waking up, nullptr otherwise.

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

include/mrs_lib/subscribe_handler.h

Classes

Public Types

Public Member Functions

Detailed Description

template<typename MessageType> class mrs_lib::SubscribeHandler< MessageType >

Constructor & Destructor Documentation

◆ SubscribeHandler() [1/9]

◆ SubscribeHandler() [2/9]

◆ SubscribeHandler() [3/9]

◆ SubscribeHandler() [4/9]

◆ SubscribeHandler() [5/9]

◆ SubscribeHandler() [6/9]

◆ SubscribeHandler() [7/9]

◆ SubscribeHandler() [8/9]

◆ SubscribeHandler() [9/9]

Member Function Documentation

◆ getMsg()

◆ getNumPublishers()

◆ hasMsg()

◆ lastMsgTime()

◆ newMsg()

◆ peekMsg()

◆ setNoMessageTimeout()

◆ start()

◆ stop()

◆ subscribedTopicName()

◆ topicName()

◆ usedMsg()

◆ waitForNew()

template<typename MessageType>
class mrs_lib::SubscribeHandler< MessageType >