edu.wpi.first.wpilibj

Class Preferences

java.lang.Object

edu.wpi.first.wpilibj.Preferences

public class Preferences
extends java.lang.Object

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

This class loads and saves from a file inside the roboRIO. The user can not access the file directly, but may modify values at specific fields which will then be automatically saved to the file by the NetworkTables server.

This class is thread safe.

This will also interact with NetworkTable by creating a table called "Preferences" with all the key-value pairs.

Method Summary

Modifier and Type	Method and Description
boolean	containsKey(java.lang.String key) Returns whether or not there is a key with the given name.
boolean	getBoolean(java.lang.String key, boolean backup) Returns the boolean at the given key.
double	getDouble(java.lang.String key, double backup) Returns the double at the given key.
float	getFloat(java.lang.String key, float backup) Returns the float at the given key.
static Preferences	getInstance() Returns the preferences instance.
int	getInt(java.lang.String key, int backup) Returns the int at the given key.
java.util.Vector	getKeys() Gets the vector of keys.
long	getLong(java.lang.String key, long backup) Returns the long at the given key.
java.lang.String	getString(java.lang.String key, java.lang.String backup) Returns the string at the given key.
void	putBoolean(java.lang.String key, boolean value) Puts the given boolean into the preferences table.
void	putDouble(java.lang.String key, double value) Puts the given double into the preferences table.
void	putFloat(java.lang.String key, float value) Puts the given float into the preferences table.
void	putInt(java.lang.String key, int value) Puts the given int into the preferences table.
void	putLong(java.lang.String key, long value) Puts the given long into the preferences table.
void	putString(java.lang.String key, java.lang.String value) Puts the given string into the preferences table.
void	remove(java.lang.String key) Remove a preference.
void	save() Deprecated. backwards compatibility shim

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getInstance

public static Preferences getInstance()

Returns the preferences instance.

Returns:

the preferences instance

getKeys

public java.util.Vector getKeys()

Gets the vector of keys.

Returns:

a vector of the keys

putString

public void putString(java.lang.String key,
                      java.lang.String value)

Puts the given string into the preferences table.

Parameters:

key - the key

value - the value

Throws:

java.lang.NullPointerException - if value is null

putInt

public void putInt(java.lang.String key,
                   int value)

Puts the given int into the preferences table.

Parameters:

key - the key

value - the value

putDouble

public void putDouble(java.lang.String key,
                      double value)

Puts the given double into the preferences table.

Parameters:

key - the key

value - the value

putFloat

public void putFloat(java.lang.String key,
                     float value)

Puts the given float into the preferences table.

Parameters:

key - the key

value - the value

putBoolean

public void putBoolean(java.lang.String key,
                       boolean value)

Puts the given boolean into the preferences table.

Parameters:

key - the key

value - the value

putLong

public void putLong(java.lang.String key,
                    long value)

Puts the given long into the preferences table.

Parameters:

key - the key

value - the value

containsKey

public boolean containsKey(java.lang.String 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

remove

public void remove(java.lang.String key)

Remove a preference.

Parameters:

key - the key

getString

public java.lang.String getString(java.lang.String key,
                                  java.lang.String backup)

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

Parameters:

key - the key

backup - the value to return if none exists in the table

Returns:

either the value in the table, or the backup

getInt

public int getInt(java.lang.String key,
                  int backup)

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

Parameters:

key - the key

backup - the value to return if none exists in the table

Returns:

either the value in the table, or the backup

getDouble

public double getDouble(java.lang.String key,
                        double backup)

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

Parameters:

key - the key

backup - the value to return if none exists in the table

Returns:

either the value in the table, or the backup

getBoolean

public boolean getBoolean(java.lang.String key,
                          boolean backup)

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

Parameters:

key - the key

backup - the value to return if none exists in the table

Returns:

either the value in the table, or the backup

getFloat

public float getFloat(java.lang.String key,
                      float backup)

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

Parameters:

key - the key

backup - the value to return if none exists in the table

Returns:

either the value in the table, or the backup

getLong

public long getLong(java.lang.String key,
                    long backup)

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

Parameters:

key - the key

backup - the value to return if none exists in the table

Returns:

either the value in the table, or the backup

save

@Deprecated
public void save()

Deprecated. backwards compatibility shim

This function is no longer required, as NetworkTables automatically saves persistent values (which all Preferences values are) periodically when running as a server.