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