aws_sdk_dynamodb/types/
_select.rs

1// Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
2
3/// When writing a match expression against `Select`, it is important to ensure
4/// your code is forward-compatible. That is, if a match arm handles a case for a
5/// feature that is supported by the service but has not been represented as an enum
6/// variant in a current version of SDK, your code should continue to work when you
7/// upgrade SDK to a future version in which the enum does include a variant for that
8/// feature.
9///
10/// Here is an example of how you can make a match expression forward-compatible:
11///
12/// ```text
13/// # let select = unimplemented!();
14/// match select {
15///     Select::AllAttributes => { /* ... */ },
16///     Select::AllProjectedAttributes => { /* ... */ },
17///     Select::Count => { /* ... */ },
18///     Select::SpecificAttributes => { /* ... */ },
19///     other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
20///     _ => { /* ... */ },
21/// }
22/// ```
23/// The above code demonstrates that when `select` represents
24/// `NewFeature`, the execution path will lead to the second last match arm,
25/// even though the enum does not contain a variant `Select::NewFeature`
26/// in the current version of SDK. The reason is that the variable `other`,
27/// created by the `@` operator, is bound to
28/// `Select::Unknown(UnknownVariantValue("NewFeature".to_owned()))`
29/// and calling `as_str` on it yields `"NewFeature"`.
30/// This match expression is forward-compatible when executed with a newer
31/// version of SDK where the variant `Select::NewFeature` is defined.
32/// Specifically, when `select` represents `NewFeature`,
33/// the execution path will hit the second last match arm as before by virtue of
34/// calling `as_str` on `Select::NewFeature` also yielding `"NewFeature"`.
35///
36/// Explicitly matching on the `Unknown` variant should
37/// be avoided for two reasons:
38/// - The inner data `UnknownVariantValue` is opaque, and no further information can be extracted.
39/// - It might inadvertently shadow other intended match arms.
40///
41#[allow(missing_docs)] // documentation missing in model
42#[non_exhaustive]
43#[derive(
44    ::std::clone::Clone, ::std::cmp::Eq, ::std::cmp::Ord, ::std::cmp::PartialEq, ::std::cmp::PartialOrd, ::std::fmt::Debug, ::std::hash::Hash,
45)]
46pub enum Select {
47    #[allow(missing_docs)] // documentation missing in model
48    AllAttributes,
49    #[allow(missing_docs)] // documentation missing in model
50    AllProjectedAttributes,
51    #[allow(missing_docs)] // documentation missing in model
52    Count,
53    #[allow(missing_docs)] // documentation missing in model
54    SpecificAttributes,
55    /// `Unknown` contains new variants that have been added since this code was generated.
56    #[deprecated(note = "Don't directly match on `Unknown`. See the docs on this enum for the correct way to handle unknown variants.")]
57    Unknown(crate::primitives::sealed_enum_unknown::UnknownVariantValue),
58}
59impl ::std::convert::From<&str> for Select {
60    fn from(s: &str) -> Self {
61        match s {
62            "ALL_ATTRIBUTES" => Select::AllAttributes,
63            "ALL_PROJECTED_ATTRIBUTES" => Select::AllProjectedAttributes,
64            "COUNT" => Select::Count,
65            "SPECIFIC_ATTRIBUTES" => Select::SpecificAttributes,
66            other => Select::Unknown(crate::primitives::sealed_enum_unknown::UnknownVariantValue(other.to_owned())),
67        }
68    }
69}
70impl ::std::str::FromStr for Select {
71    type Err = ::std::convert::Infallible;
72
73    fn from_str(s: &str) -> ::std::result::Result<Self, <Self as ::std::str::FromStr>::Err> {
74        ::std::result::Result::Ok(Select::from(s))
75    }
76}
77impl Select {
78    /// Returns the `&str` value of the enum member.
79    pub fn as_str(&self) -> &str {
80        match self {
81            Select::AllAttributes => "ALL_ATTRIBUTES",
82            Select::AllProjectedAttributes => "ALL_PROJECTED_ATTRIBUTES",
83            Select::Count => "COUNT",
84            Select::SpecificAttributes => "SPECIFIC_ATTRIBUTES",
85            Select::Unknown(value) => value.as_str(),
86        }
87    }
88    /// Returns all the `&str` representations of the enum members.
89    pub const fn values() -> &'static [&'static str] {
90        &["ALL_ATTRIBUTES", "ALL_PROJECTED_ATTRIBUTES", "COUNT", "SPECIFIC_ATTRIBUTES"]
91    }
92}
93impl ::std::convert::AsRef<str> for Select {
94    fn as_ref(&self) -> &str {
95        self.as_str()
96    }
97}
98impl Select {
99    /// Parses the enum value while disallowing unknown variants.
100    ///
101    /// Unknown variants will result in an error.
102    pub fn try_parse(value: &str) -> ::std::result::Result<Self, crate::error::UnknownVariantError> {
103        match Self::from(value) {
104            #[allow(deprecated)]
105            Self::Unknown(_) => ::std::result::Result::Err(crate::error::UnknownVariantError::new(value)),
106            known => Ok(known),
107        }
108    }
109}
110impl ::std::fmt::Display for Select {
111    fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
112        match self {
113            Select::AllAttributes => write!(f, "ALL_ATTRIBUTES"),
114            Select::AllProjectedAttributes => write!(f, "ALL_PROJECTED_ATTRIBUTES"),
115            Select::Count => write!(f, "COUNT"),
116            Select::SpecificAttributes => write!(f, "SPECIFIC_ATTRIBUTES"),
117            Select::Unknown(value) => write!(f, "{}", value),
118        }
119    }
120}
aws_sdk_dynamodb/types/_select.rs

aws_sdk_dynamodb/types/
_select.rs
