GeneralDataStorage Class Reference

#include <deal.II/algorithms/general_data_storage.h>

Inheritance diagram for GeneralDataStorage:

Public Member Functions
	GeneralDataStorage ()=default
	GeneralDataStorage (const GeneralDataStorage &)=default
	GeneralDataStorage (GeneralDataStorage &&)=default
std::size_t	size () const
void	merge (const GeneralDataStorage &other_data)
template<class Stream >
void	print_info (Stream &stream)
void	reset ()
Public Member Functions inherited from Subscriptor
	Subscriptor ()
	Subscriptor (const Subscriptor &)
	Subscriptor (Subscriptor &&) noexcept
virtual	~Subscriptor ()
Subscriptor &	operator= (const Subscriptor &)
Subscriptor &	operator= (Subscriptor &&) noexcept
void	subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
void	unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
unsigned int	n_subscriptions () const
template<typename StreamType >
void	list_subscribers (StreamType &stream) const
void	list_subscribers () const
template<class Archive >
void	serialize (Archive &ar, const unsigned int version)

Data storage and access
std::map< std::string, boost::any >	any_data
template<typename Type >
void	add_unique_copy (const std::string &name, const Type &entry)
template<typename Type >
void	add_or_overwrite_copy (const std::string &name, const Type &entry)
template<typename Type >
void	add_unique_reference (const std::string &name, Type &entry)
template<typename Type >
void	add_or_overwrite_reference (const std::string &name, Type &entry)
template<typename Type , typename Arg , typename... Args>
Type &	get_or_add_object_with_name (const std::string &name, Arg &argument, Args &... arguments)
template<typename Type , typename Arg , typename... Args>
Type &	get_or_add_object_with_name (const std::string &name, Arg &&argument, Args &&... arguments)
template<typename Type >
Type &	get_or_add_object_with_name (const std::string &name)
template<typename Type >
Type &	get_object_with_name (const std::string &name)
template<typename Type >
const Type &	get_object_with_name (const std::string &name) const
bool	stores_object_with_name (const std::string &name) const
void	remove_object_with_name (const std::string &name)
static ::ExceptionBase &	ExcNameNotFound (std::string arg1)
static ::ExceptionBase &	ExcNameHasBeenFound (std::string arg1)
static ::ExceptionBase &	ExcTypeMismatch (std::string arg1, const char *arg2, const char *arg3)

Additional Inherited Members
Static Public Member Functions inherited from Subscriptor
static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)
static ::ExceptionBase &	ExcNoSubscriber (std::string arg1, std::string arg2)

Detailed Description

This class facilitates the storage of any general data. It offers a mechanism to store any amount of data, of any type, which is then made accessible by an identifier string.

When using this class, please cite

@article{SartoriGiulianiBardelloni-2018-a,
 Author = {Sartori, Alberto and Giuliani, Nicola and
           Bardelloni, Mauro and Heltai, Luca},
 Journal = {SoftwareX},
 Pages = {318--327},
 Title = {{deal2lkit: A toolkit library for high performance
           programming in deal.II}},
 Volume = {7},
 Year = {2018}}

Author

Luca Heltai, Jean-Paul Pelteret, 2019

Definition at line 56 of file general_data_storage.h.

Constructor & Destructor Documentation

GeneralDataStorage() [1/3]

GeneralDataStorage::GeneralDataStorage ( )

default

Default constructor.

GeneralDataStorage() [2/3]

GeneralDataStorage::GeneralDataStorage ( const GeneralDataStorage &  )

default

Copy constructor.

GeneralDataStorage() [3/3]

GeneralDataStorage::GeneralDataStorage ( GeneralDataStorage &&  )

default

Move constructor.

Member Function Documentation

size()

std::size_t GeneralDataStorage::size

(

)

const

Number of objects stored by this class instance.

Definition at line 24 of file general_data_storage.cc.

merge()

void GeneralDataStorage::merge

(

const GeneralDataStorage &

other_data

)

Merge the contents of other_data with this object.

Definition at line 31 of file general_data_storage.cc.

print_info()

template<class Stream >

void GeneralDataStorage::print_info

(

Stream &

stream

)

Print the contents of the internal cache to the stream.

Each key and value pair in the any_data map are printed on an individual line, with the std::string key listed first followed by the demangled type_id of the associated mapped type.

reset()

void GeneralDataStorage::reset

(

)

Clear all data stored in this class instance.

When you call this function, it destroys all objects you asked to be stored as copies, and it forgets about the references to data you asked to store by reference. As a consequence, you are now free to destroy the objects to which references were stored at whatever time you want – before or after the current GeneralDataStorage object is destroyed.

To clarify this point, consider the following small example:

GeneralDataStorage data;
 
{
  const double some_number = ...;
  data.add_unique_reference("value", some_number);
 
  // Adding either of these next two lines could fix the
  // issue, by removing the association of some_number with data:
  // data.remove_object_with_name("value");
  // data.reset();
} // some_number goes out of scope here
 
const double some_other_number
  = data.get_object_with_name<double>("value"); // Invalid call

In the code above, the data object has a longer scope than some_number. By the time we fetch the "value" from data , the reference to some_number is no longer valid.

Similarly, for data copied into a GeneralDataStorage object one should consider the scope under which it remains valid:

double* ptr_to_some_number = null_ptr;
 
{
  GeneralDataStorage data;
  const double some_number = ...;
  data.add_unique_copy("value", some_number);
 
  ptr_to_some_number = &(data.get_object_with_name<double>("value"));
} // The copy to some_number goes out of scope here
 
const double some_other_number
  = *ptr_to_some_number; // Invalid call

Similar to the first example, we must be conscious of the fact that the copies of any Type stored by data only remains valid while the GeneralDataStorage instance in which it is stored is alive.

Furthermore, as elucidated in the last example, the copy of the class instance (owned by GeneralDataStorage) that is being pointed to is no longer alive when the reset() function is called, or when it is removed via a call to remove_object_with_name().

GeneralDataStorage data;
double* ptr_to_some_number = null_ptr;
 
{
  const double some_number = ...;
  data.add_unique_copy("value", some_number);
 
  ptr_to_some_number = &(data.get_object_with_name<double>("value"));
 
  // The copy to some_number would go out of scope when either of
  // following two calls are made:
  data.remove_object_with_name("value");
  data.reset();
}
 
const double some_other_number
  = *ptr_to_some_number; // Invalid call

Definition at line 38 of file general_data_storage.cc.

add_unique_copy()

template<typename Type >

void GeneralDataStorage::add_unique_copy	(	const std::string &	name,
		const Type &	entry
	)

Store internally a copy of the given object. The copied object is owned by this class, and is accessible via reference through the get_object_with_name() method.

This function ensures that no entry with the given name is already stored by this class instance.

add_or_overwrite_copy()

template<typename Type >

void GeneralDataStorage::add_or_overwrite_copy	(	const std::string &	name,
		const Type &	entry
	)

Store internally a copy of the given object. The copied object is owned by this class, and is accessible via reference through the get_object_with_name() method.

This function does not perform any checks to ensure that the entry with the given name is already stored by this class instance. If the name does in fact point to existing data, then this is overwritten.

add_unique_reference()

template<typename Type >

void GeneralDataStorage::add_unique_reference	(	const std::string &	name,
		Type &	entry
	)

Add a reference to an already existing object. The object is not owned by this class, and the user has to guarantee that the referenced object lives longer than this class instance. The stored reference is accessible through the get_object_with_name() method.

This function ensures that no entry with the given name is already stored by this class instance.

add_or_overwrite_reference()

template<typename Type >

void GeneralDataStorage::add_or_overwrite_reference	(	const std::string &	name,
		Type &	entry
	)

Add a reference to an already existing object. The object is not owned by this class, and the user has to guarantee that the referenced object lives longer than this class instance. The stored reference is accessible through the get_object_with_name() method.

This function does not perform any checks to ensure that the entry with the given name is already stored by this class instance. If the name does in fact point to existing data, then this is overwritten.

get_or_add_object_with_name() [1/3]

template<typename Type , typename Arg , typename... Args>

Type& GeneralDataStorage::get_or_add_object_with_name	(	const std::string &	name,
		Arg &	argument,
		Args &...	arguments
	)

Return a reference to the object with given name. If the object does not exist, then the input arguments will be used to construct an object of the given Type and a reference to this new object then be returned.

A copy of an object of type Type , which is owned by this class instance, is generated by calling its constructor with the given set of arguments. For this function, the arguments are passed as lvalue references.

get_or_add_object_with_name() [2/3]

template<typename Type , typename Arg , typename... Args>

Type& GeneralDataStorage::get_or_add_object_with_name	(	const std::string &	name,
		Arg &&	argument,
		Args &&...	arguments
	)

Return a reference to the object with given name. If the object does not exist, then the input arguments will be used to construct an object of the given Type and a reference to this new object then be returned.

A copy of an object of type Type , which is owned by this class instance, is generated by calling its constructor with the given set of arguments. In contrast to the previous function of the same name, for this function the arguments are passed as rvalue references.

get_or_add_object_with_name() [3/3]

template<typename Type >

Type& GeneralDataStorage::get_or_add_object_with_name

(

const std::string &

name

)

Same as above for default constructors.

get_object_with_name() [1/2]

template<typename Type >

Type& GeneralDataStorage::get_object_with_name

(

const std::string &

name

)

Return a reference to the object with given name.

This function throws an exception if either an object with the given name is not stored in this class, or if the object with the given name is neither of the exact specified Type nor a pointer to the Type.

get_object_with_name() [2/2]

template<typename Type >

const Type& GeneralDataStorage::get_object_with_name

(

const std::string &

name

)

const

Return a constant reference to the object with the given name.

This function throws an exception if either an object with the given name is not stored in this class, or if the object with the given name is neither of the exact specified Type nor a pointer to the Type.

stores_object_with_name()

bool GeneralDataStorage::stores_object_with_name

(

const std::string &

name

)

const

Find out if we store an object with given name.

Definition at line 45 of file general_data_storage.cc.

remove_object_with_name()

void GeneralDataStorage::remove_object_with_name

(

const std::string &

name

)

Remove the object with given name.

Definition at line 52 of file general_data_storage.cc.

Member Data Documentation

any_data

std::map<std::string, boost::any> GeneralDataStorage::any_data

private

Arbitrary user data, identified by a string.

Definition at line 340 of file general_data_storage.h.

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

• include/deal.II/algorithms/general_data_storage.h
• source/algorithms/general_data_storage.cc