csci3081::JsonHelper Class Reference

Static Public Member Functions
static const picojson::value &	GetValue (const picojson::object &obj, std::string key)
	Returns the key from json object obj as a json value, throws error if key doesn't exist. More...
static const picojson::object &	GetObject (const picojson::object &obj, std::string key)
	Returns the key from json object obj as a json object, throws error if key doesn't exist.
static const picojson::array &	GetArray (const picojson::object &obj, std::string key)
	Returns the key from json object obj as a json array, will throw an error if key doesn't exist.
static std::string	GetString (const picojson::object &obj, std::string key)
	Returns the key from json object obj as a string, will throw an error if key doesn't exist.
static double	GetDouble (const picojson::object &obj, std::string key)
	Returns the key from json object obj as a double, will throw an error if key doesn't exist.
static std::vector< float >	GetStdFloatVector (const picojson::object &obj, std::string key)
	Returns the key from json object obj as a float vector, will throw an error if key doesn't exist.
static bool	ContainsKey (const picojson::object &obj, std::string key)
	Returns a boolean value of whether the json object obj contains key or not.
static picojson::object	CreateJsonNotification ()
	Create a new json object for sending notifications.
static picojson::object	CreateJsonObject ()
	Returns a new json object.
static picojson::value	ConvertPicojsonObjectToValue (picojson::object &obj)
	Converts given obj to an equivalent picojson::value.
static void	AddValueToJsonObject (picojson::object &obj, std::string key, picojson::value val)
	Adds a picojson value to the specifiied key in a json object.
static void	AddObjectToJsonObject (picojson::object &obj, std::string key, picojson::object &val)
	Adds the latter picojson object to the former object as a value under the key 'key'.
static void	AddStringToJsonObject (picojson::object &obj, std::string key, std::string val)
	Adds a string value named key to a json object.
static void	AddFloatToJsonObject (picojson::object &obj, std::string key, float num)
	Adds a float value named key to a json object.
static void	AddStdFloatVectorToJsonObject (picojson::object &obj, std::string key, std::vector< float > vec)
	Adds a float vector value named key to a json object.
static picojson::array	CreateJsonArrayFromVector (std::vector< float > vec)
	Creates a json array from a float vector.
static void	AddStdVectorVectorFloatToJsonObject (picojson::object &obj, std::string key, std::vector< std::vector< float >> array)
	Given a picojson object, key, and vector<vector<float>> array, adds the array as the value for key in obj.
static picojson::value	EncodeArray (const vector< vector< float >> arr)
	Given a vector<vector<float>> array, returns the array as a picojson::value.
static void	PrintArray (const picojson::array &arr)
	Helper method for PrintEntityDetails.
static void	PrintKeyValues (const picojson::object &obj, std::string prefix=" ")
	Helper method for PrintEntityDetails.
static void	Print (const picojson::object &obj, std::string prefix=" ")
	Helper method for PrintEntityDetails.
static void	PrintEntityDetails (const picojson::object &val)
	Prints the details of a json object representation of an entity.

Member Function Documentation

GetValue()

static const picojson::value& csci3081::JsonHelper::GetValue ( const picojson::object &  obj, std::string  key  )

inlinestatic

Returns the key from json object obj as a json value, throws error if key doesn't exist.

USAGE: Use these querying methods to retrieve entity details from a json object. Look at project/web/scenes/umn.json lines 5-18 for an example of how an entity is represeted in a json object, or use JsonHelper::PrintEntityDetails(const picojson::object& val) to print the object's contents to the terminal.

Examples:

vector<float> position = JsonHelper::GetStdFloatVector(val, "position");

string type = JsonHelper::GetString(val, "type");

bool contains = JsonHelper::ContainsKey(val, "battery_capacity");
if (contains)...

std::vector<std::vector<float>> path = ...
...
picojson::object notification_builder = JsonHelper::CreateJsonNotification();
JsonHelper::AddStdVectorVectorFloatToObject(notification_builder, "path", path);
...
picojson::value notification_to_send = JsonHelper::ConvertJsonObjectToValue(notification_builder);
SendToObservers(notification_to_send);
...

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

• /home/user/repo/project/include/json_helper.h