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