#[non_exhaustive]pub enum PredefinedLoadMetricType {
AlbTargetGroupRequestCount,
AsgTotalCpuUtilization,
AsgTotalNetworkIn,
AsgTotalNetworkOut,
Unknown(UnknownVariantValue),
}Expand description
When writing a match expression against PredefinedLoadMetricType, 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 predefinedloadmetrictype = unimplemented!();
match predefinedloadmetrictype {
PredefinedLoadMetricType::AlbTargetGroupRequestCount => { /* ... */ },
PredefinedLoadMetricType::AsgTotalCpuUtilization => { /* ... */ },
PredefinedLoadMetricType::AsgTotalNetworkIn => { /* ... */ },
PredefinedLoadMetricType::AsgTotalNetworkOut => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when predefinedloadmetrictype represents
NewFeature, the execution path will lead to the second last match arm,
even though the enum does not contain a variant PredefinedLoadMetricType::NewFeature
in the current version of SDK. The reason is that the variable other,
created by the @ operator, is bound to
PredefinedLoadMetricType::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 PredefinedLoadMetricType::NewFeature is defined.
Specifically, when predefinedloadmetrictype represents NewFeature,
the execution path will hit the second last match arm as before by virtue of
calling as_str on PredefinedLoadMetricType::NewFeature also yielding "NewFeature".
Explicitly matching on the Unknown variant should
be avoided for two reasons:
- The inner data
UnknownVariantValueis 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
AlbTargetGroupRequestCount
AsgTotalCpuUtilization
AsgTotalNetworkIn
AsgTotalNetworkOut
Unknown(UnknownVariantValue)
Unknown contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl AsRef<str> for PredefinedLoadMetricType
impl AsRef<str> for PredefinedLoadMetricType
source§impl Clone for PredefinedLoadMetricType
impl Clone for PredefinedLoadMetricType
source§fn clone(&self) -> PredefinedLoadMetricType
fn clone(&self) -> PredefinedLoadMetricType
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moresource§impl Debug for PredefinedLoadMetricType
impl Debug for PredefinedLoadMetricType
source§impl From<&str> for PredefinedLoadMetricType
impl From<&str> for PredefinedLoadMetricType
source§impl FromStr for PredefinedLoadMetricType
impl FromStr for PredefinedLoadMetricType
source§impl Hash for PredefinedLoadMetricType
impl Hash for PredefinedLoadMetricType
source§impl Ord for PredefinedLoadMetricType
impl Ord for PredefinedLoadMetricType
source§fn cmp(&self, other: &PredefinedLoadMetricType) -> Ordering
fn cmp(&self, other: &PredefinedLoadMetricType) -> 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 PredefinedLoadMetricType
impl PartialEq for PredefinedLoadMetricType
source§fn eq(&self, other: &PredefinedLoadMetricType) -> bool
fn eq(&self, other: &PredefinedLoadMetricType) -> bool
self and other values to be equal, and is used
by ==.source§impl PartialOrd for PredefinedLoadMetricType
impl PartialOrd for PredefinedLoadMetricType
source§fn partial_cmp(&self, other: &PredefinedLoadMetricType) -> Option<Ordering>
fn partial_cmp(&self, other: &PredefinedLoadMetricType) -> 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 PredefinedLoadMetricType
impl StructuralEq for PredefinedLoadMetricType
impl StructuralPartialEq for PredefinedLoadMetricType
Auto Trait Implementations§
impl RefUnwindSafe for PredefinedLoadMetricType
impl Send for PredefinedLoadMetricType
impl Sync for PredefinedLoadMetricType
impl Unpin for PredefinedLoadMetricType
impl UnwindSafe for PredefinedLoadMetricType
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> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Qwhere Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
§impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Qwhere Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key and return true if they are equal.