#[non_exhaustive]pub enum MetricStatistic {
Average,
Maximum,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against MetricStatistic
, 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 metricstatistic = unimplemented!();
match metricstatistic {
MetricStatistic::Average => { /* ... */ },
MetricStatistic::Maximum => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when metricstatistic
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant MetricStatistic::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
MetricStatistic::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 MetricStatistic::NewFeature
is defined.
Specifically, when metricstatistic
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on MetricStatistic::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
Average
Maximum
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 MetricStatistic
impl MetricStatistic
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 MetricStatistic
impl AsRef<str> for MetricStatistic
source§impl Clone for MetricStatistic
impl Clone for MetricStatistic
source§fn clone(&self) -> MetricStatistic
fn clone(&self) -> MetricStatistic
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for MetricStatistic
impl Debug for MetricStatistic
source§impl From<&str> for MetricStatistic
impl From<&str> for MetricStatistic
source§impl FromStr for MetricStatistic
impl FromStr for MetricStatistic
source§impl Hash for MetricStatistic
impl Hash for MetricStatistic
source§impl Ord for MetricStatistic
impl Ord for MetricStatistic
source§fn cmp(&self, other: &MetricStatistic) -> Ordering
fn cmp(&self, other: &MetricStatistic) -> 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 MetricStatistic
impl PartialEq for MetricStatistic
source§fn eq(&self, other: &MetricStatistic) -> bool
fn eq(&self, other: &MetricStatistic) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd for MetricStatistic
impl PartialOrd for MetricStatistic
source§fn partial_cmp(&self, other: &MetricStatistic) -> Option<Ordering>
fn partial_cmp(&self, other: &MetricStatistic) -> 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 MetricStatistic
impl StructuralEq for MetricStatistic
impl StructuralPartialEq for MetricStatistic
Auto Trait Implementations§
impl RefUnwindSafe for MetricStatistic
impl Send for MetricStatistic
impl Sync for MetricStatistic
impl Unpin for MetricStatistic
impl UnwindSafe for MetricStatistic
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.