Trait spirit::helpers::IteratedCfgHelper

pub trait IteratedCfgHelper<O, C, Action> {
    fn apply<Extractor, ExtractedIter, Name>(
        extractor: Extractor,
        action: Action,
        name: Name,
        builder: Builder<O, C>
    ) -> Builder<O, C>
    where
        Self: Sized,
        Extractor: FnMut(&C) -> ExtractedIter + Send + 'static,
        ExtractedIter: IntoIterator<Item = Self>,
        Name: Clone + Display + Send + Sync + 'static;
}

A variant of the CfgHelper for resources that come in groups.

If an application should (for example) listen for incoming connections, it is often desirable to be able to configure multiple listening endpoints at once.

In simple words, if the IteratedCfgHelper is implemented for a type, a CfgHelper is implemented for a container of the type (eg. Vec). The extractor then extracts the vector and the helper takes care of managing multiple instances of the resource.

Single instance

If a helper is implemented in terms of IteratedCfgHelper and your application configuration contains exactly one instance, it is possible to return iter::once from the extractor, which will pretend the configuration contains a container of exactly one thing.

Some helper crates may already provide both implementations on the same type in this manner.

Required Methods

fn apply<Extractor, ExtractedIter, Name>(
    extractor: Extractor,
    action: Action,
    name: Name,
    builder: Builder<O, C>
) -> Builder<O, C>where
    Self: Sized,
    Extractor: FnMut(&C) -> ExtractedIter + Send + 'static,
    ExtractedIter: IntoIterator<Item = Self>,
    Name: Clone + Display + Send + Sync + 'static,

Perform the transformation of the builder.

It works the same way as CfgHelper::apply, only with slightly different types around the extractor.

Implementors