VariantDataModel Class Reference

VariantDataModel encapsulates QVariant and can be used as a model for any type of QVariant supported data structure (map, list, atomic variant such as double, int, ...). More...

#include <VariantDataModel.h>

Public Types
enum	VariantNodeType { Atomic , List , Map }
	The different types that can be stored in a VariantDataModel. More...

Public Member Functions
constructors
Default constructor: build an atomic invalid VariantDataModel
	VariantDataModel ()
	VariantDataModel (const QVariant &variant)
	Build an atomic VariantDataModel with the given variant value.
	VariantDataModel (const QVariantList &variant)
	Build a list VariantDataModel from the given variant list It recursively build the VariantDataModel (hence if the given variant contains atomic, list or map elements their VariantDataModel representation will be inserted in the list).
	VariantDataModel (const QVariantMap &variant)
	Build a map VariantDataModel from the given variant map It recursively build the VariantDataModel (hence if the given variant contains atomic, list or map elements their VariantDataModel representation will be inserted in the map).
	VariantDataModel (const VariantDataModel &other)
	Copy constructor.
informative methods
true if there was data modification since the instantiation or the last reset
bool	isModified () const
bool	isValid () const
	true if this is the invalid VariantDataModel
QString	typeString () const
	either "Atomic", "List" or "Map"
QString	getName ()
	same as typeString() (unused)
set/get/test
affectation to the given newValue (can be atomic, list or map)
VariantDataModel &	operator= (QVariant newValue)
QVariant	getValue () const
	get the encapsulated value (can be atomic, list or map)
QString	toString () const
	Get the QVariant value as a string (for atomic type).
	operator QString () const
	utility function to automatically convert to QString in statement
QString	toJsonString () const
	Get the string representing this model in JSON format:
void	remove ()
	Clear all encapsulated data As this method renders the data model invalid (same effect as = QVariant()), this VariantDataModel will therefore not be added to its parent in the subsequent getValue(), toString()...
bool	operator== (const VariantDataModel &other) const
	equality test (use QVariant/QVariantList/QVariantMap == operator)
bool	operator== (const QVariant &v) const
bool	operator== (const QVariantList &v) const
bool	operator== (const QVariantMap &v) const
bool	operator!= (const VariantDataModel &other) const
	inequality test (opposite of ==)
bool	operator!= (const QVariant &v) const
bool	operator!= (const QVariantList &v) const
bool	operator!= (const QVariantMap &v) const
VariantDataModel &	last ()
	Returned value depends on the VariantDataModel type:
int	size () const
	Returned value depends on the VariantDataModel type:
bool	isEmpty () const
	Returned value depends on the VariantDataModel type:
void	reset ()
	reset the modified flag (recursively for list and map)
Map management
This methods are useful when the VariantDataModel is a map
VariantDataModel &	value (const QString &key)
	Returned value depends on the VariantDataModel type:
VariantDataModel &	operator[] (const QString &key)
	Returned value depends on the VariantDataModel type:
const VariantDataModel	operator[] (const QString &key) const
	const version of operator[](QString)
bool	contains (const QString &key) const
	Returned value depends on the VariantDataModel type:
void	insert (const QString &key, const VariantDataModel &value)
	Behaviour depends on the VariantDataModel type:
void	insert (const QString &key, const QVariant &value)
	Behaviour depends on the VariantDataModel type:
int	remove (const QString &key)
	Behaviour and returned value depends on the VariantDataModel type:
List management
This methods are useful when the VariantDataModel is a List
VariantDataModel &	at (int i)
	Returned value depends on the VariantDataModel type:
VariantDataModel &	operator[] (int i)
	same as at(int)
const VariantDataModel	operator[] (int i) const
	const version of operator[](int)
bool	removeOne (const VariantDataModel &item)
	Behaviour and returned value depends on the VariantDataModel type:
bool	removeAt (int i)
	Behaviour and returned value depends on the VariantDataModel type:
void	append (const VariantDataModel &item)
	Behaviour depends on the VariantDataModel type:
STL-style iterators
QList< VariantDataModel >::iterator	begin ()
	Returns an STL-style iterator pointing to the first item in the list.
QList< VariantDataModel >::const_iterator	begin () const
	const version of begin()
QList< VariantDataModel >::iterator	end ()
	Returns an STL-style iterator pointing to the imaginary item after the last item in the list.
QList< VariantDataModel >::const_iterator	end () const
	const version of end()
QMap< QString, VariantDataModel >::iterator	beginMap ()
	Returns a STL-style iterator pointing to the first item in the map.
QMap< QString, VariantDataModel >::const_iterator	beginMap () const
	const version of beginMap()
QMap< QString, VariantDataModel >::iterator	endMap ()
	Returns an STL-style iterator pointing to the imaginary item after the last item in the map.
QMap< QString, VariantDataModel >::const_iterator	endMap () const
	const version of endMap()

Static Public Member Functions
static utility method
Build the model from the given JSON string (must be representing a JSON object)
static const VariantDataModel	fromJsonString (const QString &jsonString)
static const VariantDataModel	fromJsonObject (const QJsonObject &jsonObject)
	Build the model from the given JSON object.
static VariantDataModel &	invalid ()
	get the invalid VariantDataModel

Protected Member Functions
void	setName (const QString &name)
	set the name of the VariantDataModel

Protected Attributes
bool	isModifiedFlag
	true if there was a modification in the value, item or pair since instanciation or last reset
QString	name
	name (unused, equals to typeString())
VariantNodeType	type
	type can be Atomic, List or Map depending on how the VariantDataModel was instantiated

Static Protected Attributes
static VariantDataModel	invalidVariantDataModel
	The default VariantDataModel, an Atomic VariantDataModel with invalid status.

Detailed Description

VariantDataModel encapsulates QVariant and can be used as a model for any type of QVariant supported data structure (map, list, atomic variant such as double, int, ...).

Advantages over QVariant

• the data are accessed by reference to a VariantDataModel
• in-place adding/removing/modifying data keeps the reference unchanged while updating the encapsulated QVariant (e.g., adding a element in an array is seen as "in place" and is not done in a new array)
• STL algorithms can be used for list and maps

VariantDataModel supports atomic (single value QVariant such as string, numeric value), list (using QVariantList) and map (using QVariantMap).

VariantDataModel can be build directly from JSON string, JSON object, QVariant, QVariantList and QVariantMap. VariantDataModel offers utility methods to access, insert, remove data in place

Simple example ()

// use JSON string as input (you can also use JSON object, QVariantList, QVariantMap or QVariant)
QString rawInput = R"json({
  "name":"foo",
  "parameters":[
    {"name":"bar","value":14},
    {"name":"baz","value":"faz"}
  ]
})json";
VariantDataModel dataModel = VariantDataModel::fromJsonString(rawInput);
 
// get a ref to part of the data model
VariantDataModel& parameters = dataModel["parameters"];
 
// get values and modify in place
parameters[0]["value"] = parameters[0]["value"].getValue().toInt() / 4.0;
parameters[1]["value"] = "fuz";
 
// create from QVariantMap
VariantDataModel anotherParam = QVariantMap();
 
// add key/value
anotherParam["name"] = "camitk";
anotherParam["value"] = true;
 
// append to existing data
parameters.append(anotherParam);
 
// also available:
// remove(), removeAt(..)

Usage example

std::cout << "Name: " << dataModel["name"].toString().toStdString() << std::endl; // "foo"
for (unsigned i = 0; i < parameters.size(); i++) {
    std::cout << "- parameter " << i << ": name \"" << parameters[i]["name"].toString().toStdString() << "\", value: " << parameters[i]["value"].toString().toStdString() << std::endl;
}

Prints

Name: foo
- parameter 0: name "bar", value: 3.5
- parameter 1: name "baz", value: fuz
- parameter 2: name "camitk", value: true

using STL

for (auto p : parameters) {
    std::cout << "- parameter name \"" << p["name"].toString().toStdString() << "\", value: " << p["value"].toString().toStdString() << std::endl;
}
 
QString parameterToFind = "camitk";
auto itList = std::find_if(parameters.begin(), parameters.end(), [ &parameterToFind ](VariantDataModel const & p) {
    return p["name"].toString() == parameterToFind;
});
std::cout << (itList != parameters.end()) << std::endl; // true
 
QString valueToFind = "foo";
auto itMap = std::find_if(dataModel.beginMap(), dataModel.endMap(), [&valueToFind](const QString & value) {
    return value == valueToFind;
});
std::cout << "Key \"" << it.key() << "\" has value \"" << valueToFind \"" << std::endl;

Note

This class might need two additional members, depending on future usage:

• getErrorStatus():bool
• getErrorString():QString instead of using std::cerr for warning and errors

Member Enumeration Documentation

VariantNodeType

enum VariantDataModel::VariantNodeType

The different types that can be stored in a VariantDataModel.

Enumerator
Atomic	Atomic type (string, numeric values, boolean).
List	List of VariantDataModel.
Map	Map of <QString (key), VariantDataModel (value)>.

Constructor & Destructor Documentation

VariantDataModel() [1/5]

VariantDataModel::VariantDataModel

(

)

References Atomic, isModifiedFlag, name, and type.

Referenced by append(), at(), fromJsonObject(), fromJsonString(), insert(), insert(), invalid(), last(), operator!=(), operator=(), operator==(), operator[](), operator[](), operator[](), operator[](), removeOne(), value(), VariantDataModel(), and VariantDataModel().

VariantDataModel() [2/5]

VariantDataModel::VariantDataModel

(

const QVariant &

variant

)

Build an atomic VariantDataModel with the given variant value.

Note

no type check are done, any QVariant apart from QVariantList and QVariantMap can be stored in an atomic VariantDataModel. The user is responsible to ensure this is coherent with its data model structure

References Atomic, isModifiedFlag, List, name, type, typeString(), and VariantDataModel().

VariantDataModel() [3/5]

VariantDataModel::VariantDataModel

(

const QVariantList &

variant

)

Build a list VariantDataModel from the given variant list It recursively build the VariantDataModel (hence if the given variant contains atomic, list or map elements their VariantDataModel representation will be inserted in the list).

References isModifiedFlag, List, name, type, and typeString().

VariantDataModel() [4/5]

VariantDataModel::VariantDataModel

(

const QVariantMap &

variant

)

Build a map VariantDataModel from the given variant map It recursively build the VariantDataModel (hence if the given variant contains atomic, list or map elements their VariantDataModel representation will be inserted in the map).

References isModifiedFlag, Map, name, type, and typeString().

VariantDataModel() [5/5]

VariantDataModel::VariantDataModel

(

const VariantDataModel &

other

)

Copy constructor.

References isModifiedFlag, name, type, and VariantDataModel().

Member Function Documentation

append()

void VariantDataModel::append

(

const VariantDataModel &

item

)

Behaviour depends on the VariantDataModel type:

• for list: adds the given item to the list
• for atomic and mpa: does nothing

References getValue(), isModifiedFlag, List, type, typeString(), and VariantDataModel().

Referenced by CamiTKExtensionModelPresenter::plusButtonClicked().

at()

VariantDataModel & VariantDataModel::at

(

int

i

)

Returned value depends on the VariantDataModel type:

• For list: returns the i-th element
• For map and atomic value: returns an invalid VariantDataModel

References invalid(), List, type, typeString(), and VariantDataModel().

Referenced by operator[]().

begin() [1/2]

QList< VariantDataModel >::iterator VariantDataModel::begin

(

)

Returns an STL-style iterator pointing to the first item in the list.

Note

if the list is empty or if this VariantDataModel is not a list, this is the same as end()

begin() [2/2]

QList< VariantDataModel >::const_iterator VariantDataModel::begin

(

)

const

const version of begin()

beginMap() [1/2]

QMap< QString, VariantDataModel >::iterator VariantDataModel::beginMap

(

)

Returns a STL-style iterator pointing to the first item in the map.

Note

if the map is empty or if this VariantDataModel is not a map, this is the same as endMap()

beginMap() [2/2]

QMap< QString, VariantDataModel >::const_iterator VariantDataModel::beginMap

(

)

const

const version of beginMap()

contains()

bool VariantDataModel::contains

(

const QString &

key

)

const

Returned value depends on the VariantDataModel type:

• For map: returns true if the map contains the given key
• For atomic or list: returns false

References Map, type, and typeString().

end() [1/2]

QList< VariantDataModel >::iterator VariantDataModel::end

(

)

Returns an STL-style iterator pointing to the imaginary item after the last item in the list.

Note

if the list is empty or if this VariantDataModel is not a list, this is the same as begin()

end() [2/2]

QList< VariantDataModel >::const_iterator VariantDataModel::end

(

)

const

const version of end()

endMap() [1/2]

QMap< QString, VariantDataModel >::iterator VariantDataModel::endMap

(

)

Returns an STL-style iterator pointing to the imaginary item after the last item in the map.

Note

if the map is empty or if this VariantDataModel is not a map, this is the same as beginMap()

endMap() [2/2]

QMap< QString, VariantDataModel >::const_iterator VariantDataModel::endMap

(

)

const

const version of endMap()

fromJsonObject()

const VariantDataModel VariantDataModel::fromJsonObject ( const QJsonObject & jsonObject )

static

Build the model from the given JSON object.

References isModifiedFlag, Map, name, type, typeString(), and VariantDataModel().

fromJsonString()

const VariantDataModel VariantDataModel::fromJsonString ( const QString & jsonString )

static

References isModifiedFlag, Map, name, type, typeString(), and VariantDataModel().

getName()

QString VariantDataModel::getName

(

)

same as typeString() (unused)

References name.

getValue()

QVariant VariantDataModel::getValue

(

)

const

get the encapsulated value (can be atomic, list or map)

References Atomic, List, and type.

Referenced by append(), CamiTKPropertyFieldEditor::buildTypeDependentEditors(), camitk::CppHotPlugAction::CppHotPlugAction(), ExtensionGenerator::generate(), camitk::HotPlugAction::HotPlugAction(), camitk::HotPlugActionExtension::HotPlugActionExtension(), removeOne(), and toString().

insert() [1/2]

void VariantDataModel::insert	(	const QString &	key,
		const QVariant &	value )

Behaviour depends on the VariantDataModel type:

• For map: insert the given pair to the map (with recursive encapsulation of the given variant)
• For atom and list: does nothing

References insert(), Map, type, typeString(), value(), and VariantDataModel().

insert() [2/2]

void VariantDataModel::insert	(	const QString &	key,
		const VariantDataModel &	value )

Behaviour depends on the VariantDataModel type:

• For map: insert the given pair to the map
• For atom and list: does nothing

References isModifiedFlag, Map, type, typeString(), value(), and VariantDataModel().

Referenced by insert().

invalid()

VariantDataModel & VariantDataModel::invalid ( )

static

get the invalid VariantDataModel

References invalidVariantDataModel, and VariantDataModel().

Referenced by at(), isValid(), operator[](), operator[](), operator[](), and value().

isEmpty()

bool VariantDataModel::isEmpty

(

)

const

Returned value depends on the VariantDataModel type:

• for atomic: returns true if this is an invalid VariantDataModel, false otherwise
• for list: returns true if the list is empty
• for map: returns true if the map is empty

References Atomic, List, and type.

Referenced by size().

isModified()

bool VariantDataModel::isModified

(

)

const

References Atomic, isModifiedFlag, List, and type.

isValid()

bool VariantDataModel::isValid

(

)

const

true if this is the invalid VariantDataModel

References invalid().

Referenced by ActionTabPresenter::ActionTabPresenter(), ExtensionTabPresenter::ExtensionTabPresenter(), CamiTKExtensionModelPresenter::isPython(), camitk::HotPlugActionExtension::newHotPlugActionExtension(), and CamiTKExtensionModelPresenter::tabCloseRequest().

last()

VariantDataModel & VariantDataModel::last

(

)

Returned value depends on the VariantDataModel type:

• For atomic: returns (*this)
• For list: returns the last element of the list
• For map: returns the last value of the map

References Atomic, List, type, and VariantDataModel().

Referenced by CamiTKExtensionModelPresenter::plusButtonClicked().

operator QString()

VariantDataModel::operator QString

(

)

const

utility function to automatically convert to QString in statement

References toString().

operator!=() [1/4]

bool VariantDataModel::operator!=

(

const QVariant &

v

)

const

operator!=() [2/4]

bool VariantDataModel::operator!=

(

const QVariantList &

v

)

const

operator!=() [3/4]

bool VariantDataModel::operator!=

(

const QVariantMap &

v

)

const

operator!=() [4/4]

bool VariantDataModel::operator!=

(

const VariantDataModel &

other

)

const

inequality test (opposite of ==)

References VariantDataModel().

operator=()

VariantDataModel & VariantDataModel::operator=

(

QVariant

newValue

)

References Atomic, List, Map, type, and VariantDataModel().

operator==() [1/4]

bool VariantDataModel::operator==

(

const QVariant &

v

)

const

References Atomic, List, and type.

operator==() [2/4]

bool VariantDataModel::operator==

(

const QVariantList &

v

)

const

operator==() [3/4]

bool VariantDataModel::operator==

(

const QVariantMap &

v

)

const

operator==() [4/4]

bool VariantDataModel::operator==

(

const VariantDataModel &

other

)

const

equality test (use QVariant/QVariantList/QVariantMap == operator)

References Atomic, List, type, and VariantDataModel().

operator[]() [1/4]

VariantDataModel & VariantDataModel::operator[]

(

const QString &

key

)

Returned value depends on the VariantDataModel type:

• For map: this is the same as value(...)
• For list: if the key represents an int (e.g. "42"), this methods acts as operator[](int i), otherwise it returns an invalid VariantDataModel
• For atomic value: returns an invalid VariantDataModel

  Returns

  invalid variant if the key si not present in the map

References invalid(), List, Map, type, typeString(), and VariantDataModel().

operator[]() [2/4]

const VariantDataModel VariantDataModel::operator[]

(

const QString &

key

)

const

const version of operator[](QString)

References invalid(), List, Map, type, typeString(), and VariantDataModel().

operator[]() [3/4]

VariantDataModel & VariantDataModel::operator[]

(

int

i

)

same as at(int)

References at(), and VariantDataModel().

operator[]() [4/4]

const VariantDataModel VariantDataModel::operator[]

(

int

i

)

const

const version of operator[](int)

References invalid(), List, type, typeString(), and VariantDataModel().

remove() [1/2]

void VariantDataModel::remove

(

)

Clear all encapsulated data As this method renders the data model invalid (same effect as = QVariant()), this VariantDataModel will therefore not be added to its parent in the subsequent getValue(), toString()...

It is still present in the parent VariantDataModel (as there are no members that links the current VariantDataModel to its parent), but can be considered as removed as it won't be added to the value in any subsequent getValue(), toString()...

References Atomic, isModifiedFlag, and type.

Referenced by CamiTKExtensionModelPresenter::tabCloseRequest().

remove() [2/2]

int VariantDataModel::remove

(

const QString &

key

)

Behaviour and returned value depends on the VariantDataModel type:

• For map: removes all the item that have the given keyp and return the number of items removed (1 if the key exists, 0 otherwise)
• For atomic or list: does nothing, returns 0

References isModifiedFlag, Map, type, and typeString().

removeAt()

bool VariantDataModel::removeAt

(

int

i

)

Behaviour and returned value depends on the VariantDataModel type:

• For list: removes the item at index position i. If i is not a valid index (i.e., 0 <= i < size()), the VariantDataModel stays unmodified. Return true on success; otherwise returns false.
• for atomic and mpa: does nothing, returns false

References isModifiedFlag, List, type, and typeString().

removeOne()

bool VariantDataModel::removeOne

(

const VariantDataModel &

item

)

Behaviour and returned value depends on the VariantDataModel type:

• For list: removes the first occurrence of the item with the given value and returns true on success; otherwise returns false.
• For atomic and map: does nothing, returns false

References getValue(), isModifiedFlag, List, type, typeString(), and VariantDataModel().

reset()

void VariantDataModel::reset

(

)

reset the modified flag (recursively for list and map)

References isModifiedFlag.

setName()

void VariantDataModel::setName ( const QString & name )

protected

set the name of the VariantDataModel

References name.

size()

int VariantDataModel::size

(

)

const

Returned value depends on the VariantDataModel type:

• For atomic: returns 1 is this is not empty (i.e., if it is a valid VariantDataModel) otherwise returns 0
• For list: returns the list size
• For map: returns the map size

References Atomic, isEmpty(), List, and type.

Referenced by ActionTabPresenter::ActionTabPresenter(), CamiTKExtensionModelPresenter::CamiTKExtensionModelPresenter(), camitk::HotPlugActionExtension::declaredActionCount(), camitk::CppHotPlugActionExtension::initActions(), and CamiTKExtensionModelPresenter::plusButtonClicked().

toJsonString()

QString VariantDataModel::toJsonString

(

)

const

Get the string representing this model in JSON format:

• an Atomic returns the quoted value for strings (same as toString() but with quotes), not quoted for any other atomic values
• a List returns the equivalent JSON array ("[ ..., ... ]")
• a Map returns the equivalent JSON object ("{ ..., ... }")

References Atomic, List, and type.

toString()

QString VariantDataModel::toString

(

)

const

Get the QVariant value as a string (for atomic type).

Warning

For list and map this will return an empty string (use toJsonString() if you want the json equivalent of a VariantDataModel)

References getValue().

Referenced by CamiTKPropertyFieldEditor::buildTypeDependentEditors(), CamiTKExtensionModelPresenter::isPython(), camitk::HotPlugActionExtension::newHotPlugActionExtension(), and operator QString().

typeString()

QString VariantDataModel::typeString

(

)

const

either "Atomic", "List" or "Map"

Returns

References Atomic, List, and type.

Referenced by append(), at(), contains(), fromJsonObject(), fromJsonString(), insert(), insert(), operator[](), operator[](), operator[](), remove(), removeAt(), removeOne(), value(), VariantDataModel(), VariantDataModel(), and VariantDataModel().

value()

VariantDataModel & VariantDataModel::value

(

const QString &

key

)

Returned value depends on the VariantDataModel type:

• for map: returns the value corresponding given key
• for atomic or list: returns an invalid VariantDataModel

Note

for map: if the key is not in the map, it will be created and the returned value will be an invalid VariantDataModel

References invalid(), Map, type, typeString(), and VariantDataModel().

Referenced by insert(), and insert().

Member Data Documentation

invalidVariantDataModel

VariantDataModel VariantDataModel::invalidVariantDataModel

staticprotected

The default VariantDataModel, an Atomic VariantDataModel with invalid status.

Referenced by invalid().

isModifiedFlag

bool VariantDataModel::isModifiedFlag

protected

true if there was a modification in the value, item or pair since instanciation or last reset

Referenced by append(), fromJsonObject(), fromJsonString(), insert(), isModified(), remove(), remove(), removeAt(), removeOne(), reset(), VariantDataModel(), VariantDataModel(), VariantDataModel(), VariantDataModel(), and VariantDataModel().

name

QString VariantDataModel::name

protected

name (unused, equals to typeString())

Referenced by fromJsonObject(), fromJsonString(), getName(), setName(), VariantDataModel(), VariantDataModel(), VariantDataModel(), VariantDataModel(), and VariantDataModel().

type

VariantNodeType VariantDataModel::type

protected

type can be Atomic, List or Map depending on how the VariantDataModel was instantiated

Referenced by append(), at(), contains(), fromJsonObject(), fromJsonString(), getValue(), insert(), insert(), isEmpty(), isModified(), last(), operator=(), operator==(), operator==(), operator[](), operator[](), operator[](), remove(), remove(), removeAt(), removeOne(), size(), toJsonString(), typeString(), value(), VariantDataModel(), VariantDataModel(), VariantDataModel(), VariantDataModel(), and VariantDataModel().

---

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

• VariantDataModel.h
• VariantDataModel.cpp