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