Enum aws_sdk_ssmsap::types::HostRole

#[non_exhaustive]
pub enum HostRole {
    Leader,
    Standby,
    UnknownValue,
    Worker,
    Unknown(UnknownVariantValue),
}

When writing a match expression against HostRole, 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 hostrole = unimplemented!();
match hostrole {
    HostRole::Leader => { /* ... */ },
    HostRole::Standby => { /* ... */ },
    HostRole::UnknownValue => { /* ... */ },
    HostRole::Worker => { /* ... */ },
    other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
    _ => { /* ... */ },
}

The above code demonstrates that when hostrole represents NewFeature, the execution path will lead to the second last match arm, even though the enum does not contain a variant HostRole::NewFeature in the current version of SDK. The reason is that the variable other, created by the @ operator, is bound to HostRole::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 HostRole::NewFeature is defined. Specifically, when hostrole represents NewFeature, the execution path will hit the second last match arm as before by virtue of calling as_str on HostRole::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. Note: HostRole::Unknown has been renamed to ::UnknownValue.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Leader

Standby

UnknownValue

Note: ::Unknown has been renamed to ::UnknownValue.

Worker

Unknown(UnknownVariantValue)

Unknown contains new variants that have been added since this code was generated.

Implementations

impl HostRole

pub fn as_str(&self) -> &str

Returns the &str value of the enum member.

pub const fn values() -> &'static [&'static str]

Returns all the &str representations of the enum members.

Trait Implementations

impl AsRef<str> for HostRole

fn as_ref(&self) -> &str

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for HostRole

fn clone(&self) -> HostRole

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for HostRole

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<&str> for HostRole

fn from(s: &str) -> Self

Converts to this type from the input type.

impl FromStr for HostRole

type Err = Infallible

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, <Self as FromStr>::Err>

Parses a string s to return a value of this type.

impl Hash for HostRole

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for HostRole

fn cmp(&self, other: &HostRole) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl PartialEq for HostRole

fn eq(&self, other: &HostRole) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for HostRole

fn partial_cmp(&self, other: &HostRole) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Eq for HostRole

impl StructuralEq for HostRole

impl StructuralPartialEq for HostRole