Enum aws_sdk_dynamodb::model::StreamViewType
source · #[non_exhaustive]
pub enum StreamViewType {
KeysOnly,
NewAndOldImages,
NewImage,
OldImage,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against StreamViewType
, 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 streamviewtype = unimplemented!();
match streamviewtype {
StreamViewType::KeysOnly => { /* ... */ },
StreamViewType::NewAndOldImages => { /* ... */ },
StreamViewType::NewImage => { /* ... */ },
StreamViewType::OldImage => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when streamviewtype
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant StreamViewType::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
StreamViewType::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 StreamViewType::NewFeature
is defined.
Specifically, when streamviewtype
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on StreamViewType::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
KeysOnly
NewAndOldImages
NewImage
OldImage
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
source§impl StreamViewType
impl StreamViewType
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
2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036
pub fn serialize_structure_crate_model_stream_specification(
object: &mut aws_smithy_json::serialize::JsonObjectWriter,
input: &crate::model::StreamSpecification,
) -> Result<(), aws_smithy_http::operation::error::SerializationError> {
if let Some(var_459) = &input.stream_enabled {
object.key("StreamEnabled").boolean(*var_459);
}
if let Some(var_460) = &input.stream_view_type {
object.key("StreamViewType").string(var_460.as_str());
}
Ok(())
}
Trait Implementations§
source§impl AsRef<str> for StreamViewType
impl AsRef<str> for StreamViewType
source§impl Clone for StreamViewType
impl Clone for StreamViewType
source§fn clone(&self) -> StreamViewType
fn clone(&self) -> StreamViewType
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for StreamViewType
impl Debug for StreamViewType
source§impl From<&str> for StreamViewType
impl From<&str> for StreamViewType
source§impl FromStr for StreamViewType
impl FromStr for StreamViewType
source§impl Hash for StreamViewType
impl Hash for StreamViewType
source§impl Ord for StreamViewType
impl Ord for StreamViewType
source§fn cmp(&self, other: &StreamViewType) -> Ordering
fn cmp(&self, other: &StreamViewType) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq<StreamViewType> for StreamViewType
impl PartialEq<StreamViewType> for StreamViewType
source§fn eq(&self, other: &StreamViewType) -> bool
fn eq(&self, other: &StreamViewType) -> bool
source§impl PartialOrd<StreamViewType> for StreamViewType
impl PartialOrd<StreamViewType> for StreamViewType
source§fn partial_cmp(&self, other: &StreamViewType) -> Option<Ordering>
fn partial_cmp(&self, other: &StreamViewType) -> 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 StreamViewType
impl StructuralEq for StreamViewType
impl StructuralPartialEq for StreamViewType
Auto Trait Implementations§
impl RefUnwindSafe for StreamViewType
impl Send for StreamViewType
impl Sync for StreamViewType
impl Unpin for StreamViewType
impl UnwindSafe for StreamViewType
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.