#[non_exhaustive]pub enum LoadBalancerStateEnum {
Active,
ActiveImpaired,
Failed,
Provisioning,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against LoadBalancerStateEnum
, 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 loadbalancerstateenum = unimplemented!();
match loadbalancerstateenum {
LoadBalancerStateEnum::Active => { /* ... */ },
LoadBalancerStateEnum::ActiveImpaired => { /* ... */ },
LoadBalancerStateEnum::Failed => { /* ... */ },
LoadBalancerStateEnum::Provisioning => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when loadbalancerstateenum
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant LoadBalancerStateEnum::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
LoadBalancerStateEnum::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 LoadBalancerStateEnum::NewFeature
is defined.
Specifically, when loadbalancerstateenum
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on LoadBalancerStateEnum::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
Active
ActiveImpaired
Failed
Provisioning
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 LoadBalancerStateEnum
impl LoadBalancerStateEnum
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 LoadBalancerStateEnum
impl AsRef<str> for LoadBalancerStateEnum
source§impl Clone for LoadBalancerStateEnum
impl Clone for LoadBalancerStateEnum
source§fn clone(&self) -> LoadBalancerStateEnum
fn clone(&self) -> LoadBalancerStateEnum
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for LoadBalancerStateEnum
impl Debug for LoadBalancerStateEnum
source§impl Display for LoadBalancerStateEnum
impl Display for LoadBalancerStateEnum
source§impl From<&str> for LoadBalancerStateEnum
impl From<&str> for LoadBalancerStateEnum
source§impl FromStr for LoadBalancerStateEnum
impl FromStr for LoadBalancerStateEnum
source§impl Hash for LoadBalancerStateEnum
impl Hash for LoadBalancerStateEnum
source§impl Ord for LoadBalancerStateEnum
impl Ord for LoadBalancerStateEnum
source§fn cmp(&self, other: &LoadBalancerStateEnum) -> Ordering
fn cmp(&self, other: &LoadBalancerStateEnum) -> 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 LoadBalancerStateEnum
impl PartialEq for LoadBalancerStateEnum
source§impl PartialOrd for LoadBalancerStateEnum
impl PartialOrd for LoadBalancerStateEnum
impl Eq for LoadBalancerStateEnum
impl StructuralPartialEq for LoadBalancerStateEnum
Auto Trait Implementations§
impl Freeze for LoadBalancerStateEnum
impl RefUnwindSafe for LoadBalancerStateEnum
impl Send for LoadBalancerStateEnum
impl Sync for LoadBalancerStateEnum
impl Unpin for LoadBalancerStateEnum
impl UnwindSafe for LoadBalancerStateEnum
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
source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
source§default unsafe fn clone_to_uninit(&self, dst: *mut T)
default unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)source§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read more