#[non_exhaustive]pub enum DatabaseConnectionMethod {
Direct,
Overlay,
Unknown(UnknownVariantValue),
}Expand description
When writing a match expression against DatabaseConnectionMethod, 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 databaseconnectionmethod = unimplemented!();
match databaseconnectionmethod {
DatabaseConnectionMethod::Direct => { /* ... */ },
DatabaseConnectionMethod::Overlay => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when databaseconnectionmethod represents
NewFeature, the execution path will lead to the second last match arm,
even though the enum does not contain a variant DatabaseConnectionMethod::NewFeature
in the current version of SDK. The reason is that the variable other,
created by the @ operator, is bound to
DatabaseConnectionMethod::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 DatabaseConnectionMethod::NewFeature is defined.
Specifically, when databaseconnectionmethod represents NewFeature,
the execution path will hit the second last match arm as before by virtue of
calling as_str on DatabaseConnectionMethod::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
Direct
Overlay
Unknown(UnknownVariantValue)
Unknown contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl AsRef<str> for DatabaseConnectionMethod
impl AsRef<str> for DatabaseConnectionMethod
source§impl Clone for DatabaseConnectionMethod
impl Clone for DatabaseConnectionMethod
source§fn clone(&self) -> DatabaseConnectionMethod
fn clone(&self) -> DatabaseConnectionMethod
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moresource§impl Debug for DatabaseConnectionMethod
impl Debug for DatabaseConnectionMethod
source§impl From<&str> for DatabaseConnectionMethod
impl From<&str> for DatabaseConnectionMethod
source§impl FromStr for DatabaseConnectionMethod
impl FromStr for DatabaseConnectionMethod
source§impl Hash for DatabaseConnectionMethod
impl Hash for DatabaseConnectionMethod
source§impl Ord for DatabaseConnectionMethod
impl Ord for DatabaseConnectionMethod
source§fn cmp(&self, other: &DatabaseConnectionMethod) -> Ordering
fn cmp(&self, other: &DatabaseConnectionMethod) -> 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 DatabaseConnectionMethod
impl PartialEq for DatabaseConnectionMethod
source§fn eq(&self, other: &DatabaseConnectionMethod) -> bool
fn eq(&self, other: &DatabaseConnectionMethod) -> bool
self and other values to be equal, and is used
by ==.source§impl PartialOrd for DatabaseConnectionMethod
impl PartialOrd for DatabaseConnectionMethod
source§fn partial_cmp(&self, other: &DatabaseConnectionMethod) -> Option<Ordering>
fn partial_cmp(&self, other: &DatabaseConnectionMethod) -> 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 DatabaseConnectionMethod
impl StructuralEq for DatabaseConnectionMethod
impl StructuralPartialEq for DatabaseConnectionMethod
Auto Trait Implementations§
impl RefUnwindSafe for DatabaseConnectionMethod
impl Send for DatabaseConnectionMethod
impl Sync for DatabaseConnectionMethod
impl Unpin for DatabaseConnectionMethod
impl UnwindSafe for DatabaseConnectionMethod
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
§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key and return true if they are equal.