#[non_exhaustive]pub enum MetricSourceProvider {
CloudWatchAppInsights,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against MetricSourceProvider
, it is important to ensure
your code is forward-compatible. That is, if a match arm handles a case for a
feature that is supported by the service but has not been represented as an enum
variant in a current version of SDK, your code should continue to work when you
upgrade SDK to a future version in which the enum does include a variant for that
feature.
Here is an example of how you can make a match expression forward-compatible:
# let metricsourceprovider = unimplemented!();
match metricsourceprovider {
MetricSourceProvider::CloudWatchAppInsights => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when metricsourceprovider
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant MetricSourceProvider::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
MetricSourceProvider::Unknown(UnknownVariantValue("NewFeature".to_owned()))
and calling as_str
on it yields "NewFeature"
.
This match expression is forward-compatible when executed with a newer
version of SDK where the variant MetricSourceProvider::NewFeature
is defined.
Specifically, when metricsourceprovider
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on MetricSourceProvider::NewFeature
also yielding "NewFeature"
.
Explicitly matching on the Unknown
variant should
be avoided for two reasons:
- The inner data
UnknownVariantValue
is opaque, and no further information can be extracted. - It might inadvertently shadow other intended match arms.
Variants (Non-exhaustive)§
This enum is marked as non-exhaustive
CloudWatchAppInsights
Unknown(UnknownVariantValue)
Unknown
. See the docs on this enum for the correct way to handle unknown variants.Unknown
contains new variants that have been added since this code was generated.
Implementations§
source§impl MetricSourceProvider
impl MetricSourceProvider
sourcepub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
pub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
Parses the enum value while disallowing unknown variants.
Unknown variants will result in an error.
Trait Implementations§
source§impl AsRef<str> for MetricSourceProvider
impl AsRef<str> for MetricSourceProvider
source§impl Clone for MetricSourceProvider
impl Clone for MetricSourceProvider
source§fn clone(&self) -> MetricSourceProvider
fn clone(&self) -> MetricSourceProvider
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for MetricSourceProvider
impl Debug for MetricSourceProvider
source§impl From<&str> for MetricSourceProvider
impl From<&str> for MetricSourceProvider
source§impl FromStr for MetricSourceProvider
impl FromStr for MetricSourceProvider
source§impl Hash for MetricSourceProvider
impl Hash for MetricSourceProvider
source§impl Ord for MetricSourceProvider
impl Ord for MetricSourceProvider
source§fn cmp(&self, other: &MetricSourceProvider) -> Ordering
fn cmp(&self, other: &MetricSourceProvider) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq for MetricSourceProvider
impl PartialEq for MetricSourceProvider
source§fn eq(&self, other: &MetricSourceProvider) -> bool
fn eq(&self, other: &MetricSourceProvider) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd for MetricSourceProvider
impl PartialOrd for MetricSourceProvider
source§fn partial_cmp(&self, other: &MetricSourceProvider) -> Option<Ordering>
fn partial_cmp(&self, other: &MetricSourceProvider) -> Option<Ordering>
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read moreimpl Eq for MetricSourceProvider
impl StructuralEq for MetricSourceProvider
impl StructuralPartialEq for MetricSourceProvider
Auto Trait Implementations§
impl RefUnwindSafe for MetricSourceProvider
impl Send for MetricSourceProvider
impl Sync for MetricSourceProvider
impl Unpin for MetricSourceProvider
impl UnwindSafe for MetricSourceProvider
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.