Preferences Class Reference

#include <Preferences.h>

Inheritance diagram for Preferences:

Public Member Functions
std::vector< std::string >	GetKeys ()
std::string	GetString (const char *key, const char *defaultValue="")
int	GetString (const char *key, char *value, int valueSize, const char *defaultValue="")
int	GetInt (const char *key, int defaultValue=0)
double	GetDouble (const char *key, double defaultValue=0.0)
float	GetFloat (const char *key, float defaultValue=0.0)
bool	GetBoolean (const char *key, bool defaultValue=false)
INT64	GetLong (const char *key, INT64 defaultValue=0)
void	PutString (const char *key, const char *value)
void	PutInt (const char *key, int value)
void	PutDouble (const char *key, double value)
void	PutFloat (const char *key, float value)
void	PutBoolean (const char *key, bool value)
void	PutLong (const char *key, INT64 value)
void	Save ()
bool	ContainsKey (const char *key)
void	Remove (const char *key)
void	ValueChanged (ITable *source, const std::string &key, EntryValue value, bool isNew)
Public Member Functions inherited from ErrorBase
virtual Error &	GetError ()
	Retrieve the current error. Get the current error information associated with this sensor.
virtual const Error &	GetError () const
virtual void	SetErrnoError (const char *contextMessage, const char *filename, const char *function, uint32_t lineNumber) const
	Set error information associated with a C library call that set an error to the "errno" global variable. More...
virtual void	SetImaqError (int success, const char *contextMessage, const char *filename, const char *function, uint32_t lineNumber) const
	Set the current error information associated from the nivision Imaq API. More...
virtual void	SetError (Error::Code code, const char *contextMessage, const char *filename, const char *function, uint32_t lineNumber) const
	Set the current error information associated with this sensor. More...
virtual void	SetWPIError (const char *errorMessage, const char *contextMessage, const char *filename, const char *function, uint32_t lineNumber) const
	Set the current error information associated with this sensor. More...
virtual void	CloneError (ErrorBase *rhs) const
virtual void	ClearError () const
	Clear the current error information associated with this sensor.
virtual bool	StatusIsFatal () const
	Check if the current error code represents a fatal error. More...

Static Public Member Functions
static Preferences *	GetInstance ()
Static Public Member Functions inherited from ErrorBase
static void	SetGlobalError (Error::Code code, const char *contextMessage, const char *filename, const char *function, uint32_t lineNumber)
static void	SetGlobalWPIError (const char *errorMessage, const char *contextMessage, const char *filename, const char *function, uint32_t lineNumber)
static Error &	GetGlobalError ()

Additional Inherited Members
Protected Member Functions inherited from ErrorBase
	ErrorBase ()
	Initialize the instance status to 0 for now.
Protected Attributes inherited from ErrorBase
Error	m_error
Static Protected Attributes inherited from ErrorBase
static SEM_ID	_globalErrorMutex = semMCreate(SEM_Q_PRIORITY | SEM_DELETE_SAFE | SEM_INVERSION_SAFE)
static Error	_globalError

Detailed Description

The preferences class provides a relatively simple way to save important values to the cRIO to access the next time the cRIO is booted.

This class loads and saves from a file inside the cRIO. The user can not access the file directly, but may modify values at specific fields which will then be saved to the file when Save() is called.

This class is thread safe.

This will also interact with NetworkTable by creating a table called "Preferences" with all the key-value pairs. To save using NetworkTable, simply set the boolean at position "~S A V E~" to true. Also, if the value of any variable is " in the NetworkTable, then that represents non-existence in the Preferences table

Member Function Documentation

bool Preferences::ContainsKey

(

const char *

key

)

Returns whether or not there is a key with the given name.

Parameters

key

the key

Returns

if there is a value at the given key

bool Preferences::GetBoolean	(	const char *	key,
		bool	defaultValue = false
	)

Returns the boolean at the given key. If this table does not have a value for that position, then the given defaultValue value will be returned.

Parameters

key	the key
defaultValue	the value to return if none exists in the table

Returns

either the value in the table, or the defaultValue

double Preferences::GetDouble	(	const char *	key,
		double	defaultValue = 0.0
	)

Returns the double at the given key. If this table does not have a value for that position, then the given defaultValue value will be returned.

Parameters

key	the key
defaultValue	the value to return if none exists in the table

Returns

either the value in the table, or the defaultValue

float Preferences::GetFloat	(	const char *	key,
		float	defaultValue = 0.0
	)

Returns the float at the given key. If this table does not have a value for that position, then the given defaultValue value will be returned.

Parameters

key	the key
defaultValue	the value to return if none exists in the table

Returns

either the value in the table, or the defaultValue

Preferences * Preferences::GetInstance ( )

static

Get the one and only Preferences object

Returns

pointer to the Preferences

int Preferences::GetInt	(	const char *	key,
		int	defaultValue = 0
	)

Returns the int at the given key. If this table does not have a value for that position, then the given defaultValue value will be returned.

Parameters

key	the key
defaultValue	the value to return if none exists in the table

Returns

either the value in the table, or the defaultValue

std::vector< std::string > Preferences::GetKeys

(

)

Returns a vector of all the keys

Returns

a vector of the keys

INT64 Preferences::GetLong	(	const char *	key,
		INT64	defaultValue = 0
	)

Returns the long (INT64) at the given key. If this table does not have a value for that position, then the given defaultValue value will be returned.

Parameters

key	the key
defaultValue	the value to return if none exists in the table

Returns

either the value in the table, or the defaultValue

std::string Preferences::GetString	(	const char *	key,
		const char *	defaultValue = ""
	)

Returns the string at the given key. If this table does not have a value for that position, then the given defaultValue will be returned.

Parameters

key	the key
defaultValue	the value to return if none exists in the table

Returns

either the value in the table, or the defaultValue

int Preferences::GetString	(	const char *	key,
		char *	value,
		int	valueSize,
		const char *	defaultValue = ""
	)

Returns the string at the given key. If this table does not have a value for that position, then the given defaultValue will be returned.

Parameters

key	the key
value	the buffer to copy the value into
valueSize	the size of value
defaultValue	the value to return if none exists in the table

Returns

The size of the returned string

void Preferences::PutBoolean	(	const char *	key,
		bool	value
	)

Puts the given boolean into the preferences table.

The key may not have any whitespace nor an equals sign

This will NOT save the value to memory between power cycles, to do that you must call Save() (which must be used with care) at some point after calling this.

Parameters

key	the key
value	the value

void Preferences::PutDouble	(	const char *	key,
		double	value
	)

Puts the given double into the preferences table.

The key may not have any whitespace nor an equals sign

This will NOT save the value to memory between power cycles, to do that you must call Save() (which must be used with care) at some point after calling this.

Parameters

key	the key
value	the value

void Preferences::PutFloat	(	const char *	key,
		float	value
	)

Puts the given float into the preferences table.

The key may not have any whitespace nor an equals sign

This will NOT save the value to memory between power cycles, to do that you must call Save() (which must be used with care) at some point after calling this.

Parameters

key	the key
value	the value

void Preferences::PutInt	(	const char *	key,
		int	value
	)

Puts the given int into the preferences table.

The key may not have any whitespace nor an equals sign

This will NOT save the value to memory between power cycles, to do that you must call Save() (which must be used with care) at some point after calling this.

Parameters

key	the key
value	the value

void Preferences::PutLong	(	const char *	key,
		INT64	value
	)

Puts the given long (INT64) into the preferences table.

The key may not have any whitespace nor an equals sign

This will NOT save the value to memory between power cycles, to do that you must call Save() (which must be used with care) at some point after calling this.

Parameters

key	the key
value	the value

void Preferences::PutString	(	const char *	key,
		const char *	value
	)

Puts the given string into the preferences table.

The value may not have quotation marks, nor may the key have any whitespace nor an equals sign

This will NOT save the value to memory between power cycles, to do that you must call Save() (which must be used with care). at some point after calling this.

Parameters

key	the key
value	the value

void Preferences::Remove

(

const char *

key

)

Remove a preference

Parameters

key

the key

void Preferences::Save

(

)

Saves the preferences to a file on the cRIO.

This should NOT be called often. Too many writes can damage the cRIO's flash memory. While it is ok to save once or twice a match, this should never be called every run of IterativeRobot#TeleopPeriodic(), etc.

The actual writing of the file is done in a separate thread. However, any call to a get or put method will wait until the table is fully saved before continuing.

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

• Preferences.h
• Preferences.cpp