Trait icu_provider::iter::KeyedDataProvider

pub trait KeyedDataProvider {
    fn supports_key(resc_key: &ResourceKey) -> Result<(), Error>;

    fn or_else_supports_key(
        err: Error, 
        resc_key: &ResourceKey
    ) -> Result<(), Error> { ... }
}

A DataProvider whose supported keys are known statically at compile time.

Implementing this trait means that a DataProvider is built to support a specific set of keys; for example, by transforming those keys from an external data source.

TODO: When const_trait_impl is stable, most implementations of this trait should be const.

Required methods

fn supports_key(resc_key: &ResourceKey) -> Result<(), Error>

Given a ResourceKey, checks whether this type of DataProvider supports it.

Returns Ok if the key is supported, or an Error with more information if not. The Error should be either UnsupportedCategory or UnsupportedResourceKey.

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Provided methods

fn or_else_supports_key(err: Error, resc_key: &ResourceKey) -> Result<(), Error>

Auto-implemented function that enables chaining of KeyedDataProviders while preserving UnsupportedResourceKey.

Examples

DataProviderA::supports_key(resc_key)
    .or_else(|err| DataProviderB::or_else_supports_key(err, resc_key))
    .or_else(|err| DataProviderC::or_else_supports_key(err, resc_key))

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Implementors

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