#[non_exhaustive]
pub enum RefreshStrategy {
Rolling,
Unknown(UnknownVariantValue),
}Expand description
When writing a match expression against RefreshStrategy, 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 refreshstrategy = unimplemented!();
match refreshstrategy {
RefreshStrategy::Rolling => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when refreshstrategy represents
NewFeature, the execution path will lead to the second last match arm,
even though the enum does not contain a variant RefreshStrategy::NewFeature
in the current version of SDK. The reason is that the variable other,
created by the @ operator, is bound to
RefreshStrategy::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 RefreshStrategy::NewFeature is defined.
Specifically, when refreshstrategy represents NewFeature,
the execution path will hit the second last match arm as before by virtue of
calling as_str on RefreshStrategy::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
Rolling
Unknown(UnknownVariantValue)
Unknown contains new variants that have been added since this code was generated.
Implementations§
source§impl RefreshStrategy
impl RefreshStrategy
sourcepub fn as_str(&self) -> &str
pub fn as_str(&self) -> &str
Returns the &str value of the enum member.
Examples found in repository?
More examples
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pub fn serialize_operation_crate_operation_start_instance_refresh(
input: &crate::input::StartInstanceRefreshInput,
) -> Result<aws_smithy_http::body::SdkBody, aws_smithy_http::operation::error::SerializationError> {
let mut out = String::new();
#[allow(unused_mut)]
let mut writer =
aws_smithy_query::QueryWriter::new(&mut out, "StartInstanceRefresh", "2011-01-01");
#[allow(unused_mut)]
let mut scope_526 = writer.prefix("AutoScalingGroupName");
if let Some(var_527) = &input.auto_scaling_group_name {
scope_526.string(var_527);
}
#[allow(unused_mut)]
let mut scope_528 = writer.prefix("Strategy");
if let Some(var_529) = &input.strategy {
scope_528.string(var_529.as_str());
}
#[allow(unused_mut)]
let mut scope_530 = writer.prefix("DesiredConfiguration");
if let Some(var_531) = &input.desired_configuration {
crate::query_ser::serialize_structure_crate_model_desired_configuration(
scope_530, var_531,
)?;
}
#[allow(unused_mut)]
let mut scope_532 = writer.prefix("Preferences");
if let Some(var_533) = &input.preferences {
crate::query_ser::serialize_structure_crate_model_refresh_preferences(scope_532, var_533)?;
}
writer.finish();
Ok(aws_smithy_http::body::SdkBody::from(out))
}Trait Implementations§
source§impl AsRef<str> for RefreshStrategy
impl AsRef<str> for RefreshStrategy
source§impl Clone for RefreshStrategy
impl Clone for RefreshStrategy
source§fn clone(&self) -> RefreshStrategy
fn clone(&self) -> RefreshStrategy
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moresource§impl Debug for RefreshStrategy
impl Debug for RefreshStrategy
source§impl From<&str> for RefreshStrategy
impl From<&str> for RefreshStrategy
source§impl FromStr for RefreshStrategy
impl FromStr for RefreshStrategy
source§impl Hash for RefreshStrategy
impl Hash for RefreshStrategy
source§impl Ord for RefreshStrategy
impl Ord for RefreshStrategy
source§fn cmp(&self, other: &RefreshStrategy) -> Ordering
fn cmp(&self, other: &RefreshStrategy) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq<RefreshStrategy> for RefreshStrategy
impl PartialEq<RefreshStrategy> for RefreshStrategy
source§fn eq(&self, other: &RefreshStrategy) -> bool
fn eq(&self, other: &RefreshStrategy) -> bool
source§impl PartialOrd<RefreshStrategy> for RefreshStrategy
impl PartialOrd<RefreshStrategy> for RefreshStrategy
source§fn partial_cmp(&self, other: &RefreshStrategy) -> Option<Ordering>
fn partial_cmp(&self, other: &RefreshStrategy) -> 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 RefreshStrategy
impl StructuralEq for RefreshStrategy
impl StructuralPartialEq for RefreshStrategy
Auto Trait Implementations§
impl RefUnwindSafe for RefreshStrategy
impl Send for RefreshStrategy
impl Sync for RefreshStrategy
impl Unpin for RefreshStrategy
impl UnwindSafe for RefreshStrategy
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.