[−][src]Trait justconfig::item::ValueExtractor

pub trait ValueExtractor<T: FromStr> {
    pub fn try_value(self) -> Result<Option<T>, ConfigError>;

    pub fn value(self) -> Result<T, ConfigError>;

    pub fn values<R: RangeBounds<usize>>(
        self, 
        range: R
    ) -> Result<Vec<T>, ConfigError>;
}

Trait implemented for TypedItem and StringItem to allow retrieval of the stored config value.

This Trait is implemented for Result<TypedItem<T>, ConfigError> and Result<StringItem, ConfigError>. This makes sure that the methods can be called on the raw StringItems and on the TypedItems returned by validators.

The Implementation for StringItem will do the same conversion that is normally done when calling a validator.

Required methods

pub fn try_value(self) -> Result<Option<T>, ConfigError>[src]

Returns a configuration value if it exists or ´None´ otherwise.

An error is only returned if one of the following occures:

  • The value of the configuration item could not be converted into the required data type.
  • A processor or validator returned an error.
  • There is more that one value available.

This method should be used to return optional configuration values. A default value can be provided by using unwrap_or.

Example

let myvalue: u32 = conf.get(ConfPath::from(&["myvalue"])).try_value().expect("Error").unwrap_or(0);

pub fn value(self) -> Result<T, ConfigError>[src]

Returns a configuration value or raises an error if it does not exists.

This method works like try_value() but returns an error if the configuration item does not exist.

This method should be used to return mandatory configuration values that should result in an error if they are not found.

Example

let myvalue: u32 = conf.get(ConfPath::from(&["myvalue"])).value().expect("Error or not found");

pub fn values<R: RangeBounds<usize>>(
    self,
    range: R
) -> Result<Vec<T>, ConfigError>[src]

Returns all configuration values for a configuration item.

This is the only method that allows more than one configuration value to exist. Use this method to read multi value items. If the configuration item does not exist, an empty array is returned.

The method accepts a range to specify how many configuration values can be set for this item. If any number of configuration values are acceptible, just specify ... If the number of values should be limited, specify a range.

Example

let myvalue: Vec<u32> = conf.get(ConfPath::from(&["myvalue"])).values(..).expect("Error");

If there must be at least one instance of myvalue specify a range of 1..:

let myvalue: Vec<u32> = conf.get(ConfPath::from(&["myvalue"])).values(1..).expect("Error");

If the number of values should be limited to at most 3 values the range must be ..=3.

Loading content...

Implementations on Foreign Types

impl<T: FromStr> ValueExtractor<T> for Result<TypedItem<T>, ConfigError>[src]

impl<T: FromStr> ValueExtractor<T> for Result<StringItem, ConfigError> where
    T::Err: Error + 'static, [src]

Loading content...

Implementors

Loading content...