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