Enum swagger::nullable_format::Nullable
source · pub enum Nullable<T> {
Null,
Present(T),
}
Expand description
The Nullable type. Represents a value which may be specified as null on an API. Note that this is distinct from a value that is optional and not present!
Nullable implements many of the same methods as the Option type (map, unwrap, etc).
Variants§
Implementations§
source§impl<T> Nullable<T>
impl<T> Nullable<T>
sourcepub fn is_present(&self) -> bool
pub fn is_present(&self) -> bool
Returns true
if the Nullable is a Present
value.
Examples
let x: Nullable<u32> = Nullable::Present(2);
assert_eq!(x.is_present(), true);
let x: Nullable<u32> = Nullable::Null;
assert_eq!(x.is_present(), false);
sourcepub fn is_null(&self) -> bool
pub fn is_null(&self) -> bool
Returns true
if the Nullable is a Null
value.
Examples
let x: Nullable<u32> = Nullable::Present(2);
assert_eq!(x.is_null(), false);
let x: Nullable<u32> = Nullable::Null;
assert_eq!(x.is_null(), true);
sourcepub fn as_ref(&self) -> Nullable<&T>
pub fn as_ref(&self) -> Nullable<&T>
Converts from Nullable<T>
to Nullable<&T>
.
Examples
Convert an Nullable<
String
>
into a Nullable<
usize
>
, preserving the original.
The map
method takes the self
argument by value, consuming the original,
so this technique uses as_ref
to first take a Nullable
to a reference
to the value inside the original.
let num_as_str: Nullable<String> = Nullable::Present("10".to_string());
// First, cast `Nullable<String>` to `Nullable<&String>` with `as_ref`,
// then consume *that* with `map`, leaving `num_as_str` on the stack.
let num_as_int: Nullable<usize> = num_as_str.as_ref().map(|n| n.len());
println!("still can print num_as_str: {:?}", num_as_str);
sourcepub fn as_mut(&mut self) -> Nullable<&mut T>
pub fn as_mut(&mut self) -> Nullable<&mut T>
Converts from Nullable<T>
to Nullable<&mut T>
.
Examples
let mut x = Nullable::Present(2);
match x.as_mut() {
Nullable::Present(v) => *v = 42,
Nullable::Null => {},
}
assert_eq!(x, Nullable::Present(42));
sourcepub fn expect(self, msg: &str) -> T
pub fn expect(self, msg: &str) -> T
Unwraps a Nullable, yielding the content of a Nullable::Present
.
Panics
Panics if the value is a Nullable::Null
with a custom panic message provided by
msg
.
Examples
let x = Nullable::Present("value");
assert_eq!(x.expect("the world is ending"), "value");
let x: Nullable<&str> = Nullable::Null;
x.expect("the world is ending"); // panics with `the world is ending`
sourcepub fn unwrap(self) -> T
pub fn unwrap(self) -> T
Moves the value v
out of the Nullable<T>
if it is Nullable::Present(v)
.
In general, because this function may panic, its use is discouraged.
Instead, prefer to use pattern matching and handle the Nullable::Null
case explicitly.
Panics
Panics if the self value equals Nullable::Null
.
Examples
let x = Nullable::Present("air");
assert_eq!(x.unwrap(), "air");
let x: Nullable<&str> = Nullable::Null;
assert_eq!(x.unwrap(), "air"); // fails
sourcepub fn unwrap_or(self, def: T) -> T
pub fn unwrap_or(self, def: T) -> T
Returns the contained value or a default.
Examples
assert_eq!(Nullable::Present("car").unwrap_or("bike"), "car");
assert_eq!(Nullable::Null.unwrap_or("bike"), "bike");
sourcepub fn unwrap_or_else<F: FnOnce() -> T>(self, f: F) -> T
pub fn unwrap_or_else<F: FnOnce() -> T>(self, f: F) -> T
Returns the contained value or computes it from a closure.
Examples
let k = 10;
assert_eq!(Nullable::Present(4).unwrap_or_else(|| 2 * k), 4);
assert_eq!(Nullable::Null.unwrap_or_else(|| 2 * k), 20);
sourcepub fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Nullable<U>
pub fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Nullable<U>
Maps a Nullable<T>
to Nullable<U>
by applying a function to a contained value.
Examples
Convert a Nullable<
String
>
into a Nullable<
usize
>
, consuming the original:
let maybe_some_string = Nullable::Present(String::from("Hello, World!"));
// `Nullable::map` takes self *by value*, consuming `maybe_some_string`
let maybe_some_len = maybe_some_string.map(|s| s.len());
assert_eq!(maybe_some_len, Nullable::Present(13));
sourcepub fn map_or<U, F: FnOnce(T) -> U>(self, default: U, f: F) -> U
pub fn map_or<U, F: FnOnce(T) -> U>(self, default: U, f: F) -> U
Applies a function to the contained value (if any),
or returns a default
(if not).
Examples
let x = Nullable::Present("foo");
assert_eq!(x.map_or(42, |v| v.len()), 3);
let x: Nullable<&str> = Nullable::Null;
assert_eq!(x.map_or(42, |v| v.len()), 42);
sourcepub fn map_or_else<U, D: FnOnce() -> U, F: FnOnce(T) -> U>(
self,
default: D,
f: F
) -> U
pub fn map_or_else<U, D: FnOnce() -> U, F: FnOnce(T) -> U>( self, default: D, f: F ) -> U
Applies a function to the contained value (if any),
or computes a default
(if not).
Examples
let k = 21;
let x = Nullable::Present("foo");
assert_eq!(x.map_or_else(|| 2 * k, |v| v.len()), 3);
let x: Nullable<&str> = Nullable::Null;
assert_eq!(x.map_or_else(|| 2 * k, |v| v.len()), 42);
sourcepub fn ok_or<E>(self, err: E) -> Result<T, E>
pub fn ok_or<E>(self, err: E) -> Result<T, E>
Transforms the Nullable<T>
into a Result<T, E>
, mapping Nullable::Present(v)
to
Ok(v)
and Nullable::Null
to Err(err)
.
Examples
let x = Nullable::Present("foo");
assert_eq!(x.ok_or(0), Ok("foo"));
let x: Nullable<&str> = Nullable::Null;
assert_eq!(x.ok_or(0), Err(0));
sourcepub fn ok_or_else<E, F: FnOnce() -> E>(self, err: F) -> Result<T, E>
pub fn ok_or_else<E, F: FnOnce() -> E>(self, err: F) -> Result<T, E>
Transforms the Nullable<T>
into a Result<T, E>
, mapping Nullable::Present(v)
to
Ok(v)
and Nullable::Null
to Err(err())
.
Examples
let x = Nullable::Present("foo");
assert_eq!(x.ok_or_else(|| 0), Ok("foo"));
let x: Nullable<&str> = Nullable::Null;
assert_eq!(x.ok_or_else(|| 0), Err(0));
sourcepub fn and<U>(self, optb: Nullable<U>) -> Nullable<U>
pub fn and<U>(self, optb: Nullable<U>) -> Nullable<U>
Returns Nullable::Null
if the Nullable is Nullable::Null
, otherwise returns optb
.
Examples
let x = Nullable::Present(2);
let y: Nullable<&str> = Nullable::Null;
assert_eq!(x.and(y), Nullable::Null);
let x: Nullable<u32> = Nullable::Null;
let y = Nullable::Present("foo");
assert_eq!(x.and(y), Nullable::Null);
let x = Nullable::Present(2);
let y = Nullable::Present("foo");
assert_eq!(x.and(y), Nullable::Present("foo"));
let x: Nullable<u32> = Nullable::Null;
let y: Nullable<&str> = Nullable::Null;
assert_eq!(x.and(y), Nullable::Null);
sourcepub fn and_then<U, F: FnOnce(T) -> Nullable<U>>(self, f: F) -> Nullable<U>
pub fn and_then<U, F: FnOnce(T) -> Nullable<U>>(self, f: F) -> Nullable<U>
Returns Nullable::Null
if the Nullable is Nullable::Null
, otherwise calls f
with the
wrapped value and returns the result.
Some languages call this operation flatmap.
Examples
fn sq(x: u32) -> Nullable<u32> { Nullable::Present(x * x) }
fn nope(_: u32) -> Nullable<u32> { Nullable::Null }
assert_eq!(Nullable::Present(2).and_then(sq).and_then(sq), Nullable::Present(16));
assert_eq!(Nullable::Present(2).and_then(sq).and_then(nope), Nullable::Null);
assert_eq!(Nullable::Present(2).and_then(nope).and_then(sq), Nullable::Null);
assert_eq!(Nullable::Null.and_then(sq).and_then(sq), Nullable::Null);
sourcepub fn or(self, optb: Nullable<T>) -> Nullable<T>
pub fn or(self, optb: Nullable<T>) -> Nullable<T>
Returns the Nullable if it contains a value, otherwise returns optb
.
Examples
let x = Nullable::Present(2);
let y = Nullable::Null;
assert_eq!(x.or(y), Nullable::Present(2));
let x = Nullable::Null;
let y = Nullable::Present(100);
assert_eq!(x.or(y), Nullable::Present(100));
let x = Nullable::Present(2);
let y = Nullable::Present(100);
assert_eq!(x.or(y), Nullable::Present(2));
let x: Nullable<u32> = Nullable::Null;
let y = Nullable::Null;
assert_eq!(x.or(y), Nullable::Null);
sourcepub fn or_else<F: FnOnce() -> Nullable<T>>(self, f: F) -> Nullable<T>
pub fn or_else<F: FnOnce() -> Nullable<T>>(self, f: F) -> Nullable<T>
Returns the Nullable if it contains a value, otherwise calls f
and
returns the result.
Examples
fn nobody() -> Nullable<&'static str> { Nullable::Null }
fn vikings() -> Nullable<&'static str> { Nullable::Present("vikings") }
assert_eq!(Nullable::Present("barbarians").or_else(vikings),
Nullable::Present("barbarians"));
assert_eq!(Nullable::Null.or_else(vikings), Nullable::Present("vikings"));
assert_eq!(Nullable::Null.or_else(nobody), Nullable::Null);
source§impl<T: Default> Nullable<T>
impl<T: Default> Nullable<T>
sourcepub fn unwrap_or_default(self) -> T
pub fn unwrap_or_default(self) -> T
Returns the contained value or a default
Consumes the self
argument then, if Nullable::Present
, returns the contained
value, otherwise if Nullable::Null
, returns the default value for that
type.
Examples
let x = Nullable::Present(42);
assert_eq!(42, x.unwrap_or_default());
let y: Nullable<i32> = Nullable::Null;
assert_eq!(0, y.unwrap_or_default());
Trait Implementations§
source§impl<'de, T> Deserialize<'de> for Nullable<T>where
T: DeserializeOwned,
Available on crate feature serdejson
only.
impl<'de, T> Deserialize<'de> for Nullable<T>where T: DeserializeOwned,
serdejson
only.source§fn deserialize<D>(deserializer: D) -> Result<Nullable<T>, D::Error>where
D: Deserializer<'de>,
fn deserialize<D>(deserializer: D) -> Result<Nullable<T>, D::Error>where D: Deserializer<'de>,
source§impl<T: PartialEq> PartialEq<Nullable<T>> for Nullable<T>
impl<T: PartialEq> PartialEq<Nullable<T>> for Nullable<T>
source§impl<T: PartialOrd> PartialOrd<Nullable<T>> for Nullable<T>
impl<T: PartialOrd> PartialOrd<Nullable<T>> for Nullable<T>
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 moresource§impl<T> Serialize for Nullable<T>where
T: Serialize,
Available on crate feature serdejson
only.
impl<T> Serialize for Nullable<T>where T: Serialize,
serdejson
only.source§impl<T> Validate for Nullable<T>where
T: Validate,
Available on crate feature serdevalid
only.
impl<T> Validate for Nullable<T>where T: Validate,
serdevalid
only.source§impl<T, U> ValidateCompositedEnumerate<T> for Nullable<U>where
T: Copy,
U: ValidateCompositedEnumerate<T>,
Available on crate feature serdevalid
only.
impl<T, U> ValidateCompositedEnumerate<T> for Nullable<U>where T: Copy, U: ValidateCompositedEnumerate<T>,
serdevalid
only.fn validate_composited_enumerate( &self, limit: T ) -> Result<(), Composited<EnumerateError>>
source§impl<T, U> ValidateCompositedExclusiveMaximum<T> for Nullable<U>where
T: Copy,
U: ValidateCompositedExclusiveMaximum<T>,
Available on crate feature serdevalid
only.
impl<T, U> ValidateCompositedExclusiveMaximum<T> for Nullable<U>where T: Copy, U: ValidateCompositedExclusiveMaximum<T>,
serdevalid
only.fn validate_composited_exclusive_maximum( &self, limit: T ) -> Result<(), Composited<ExclusiveMaximumError>>
source§impl<T, U> ValidateCompositedExclusiveMinimum<T> for Nullable<U>where
T: Copy,
U: ValidateCompositedExclusiveMinimum<T>,
Available on crate feature serdevalid
only.
impl<T, U> ValidateCompositedExclusiveMinimum<T> for Nullable<U>where T: Copy, U: ValidateCompositedExclusiveMinimum<T>,
serdevalid
only.fn validate_composited_exclusive_minimum( &self, limit: T ) -> Result<(), Composited<ExclusiveMinimumError>>
source§impl<T> ValidateCompositedMaxLength for Nullable<T>where
T: ValidateCompositedMaxLength,
Available on crate feature serdevalid
only.
impl<T> ValidateCompositedMaxLength for Nullable<T>where T: ValidateCompositedMaxLength,
serdevalid
only.fn validate_composited_max_length( &self, limit: usize ) -> Result<(), Composited<MaxLengthError>>
source§impl<T> ValidateCompositedMaxProperties for Nullable<T>where
T: ValidateCompositedMaxProperties,
Available on crate feature serdevalid
only.
impl<T> ValidateCompositedMaxProperties for Nullable<T>where T: ValidateCompositedMaxProperties,
serdevalid
only.fn validate_composited_max_properties( &self, limit: usize ) -> Result<(), Composited<MaxPropertiesError>>
source§impl<T, U> ValidateCompositedMaximum<T> for Nullable<U>where
T: Copy,
U: ValidateCompositedMaximum<T>,
Available on crate feature serdevalid
only.
impl<T, U> ValidateCompositedMaximum<T> for Nullable<U>where T: Copy, U: ValidateCompositedMaximum<T>,
serdevalid
only.fn validate_composited_maximum( &self, limit: T ) -> Result<(), Composited<MaximumError>>
source§impl<T> ValidateCompositedMinLength for Nullable<T>where
T: ValidateCompositedMinLength,
Available on crate feature serdevalid
only.
impl<T> ValidateCompositedMinLength for Nullable<T>where T: ValidateCompositedMinLength,
serdevalid
only.fn validate_composited_min_length( &self, limit: usize ) -> Result<(), Composited<MinLengthError>>
source§impl<T> ValidateCompositedMinProperties for Nullable<T>where
T: ValidateCompositedMinProperties,
Available on crate feature serdevalid
only.
impl<T> ValidateCompositedMinProperties for Nullable<T>where T: ValidateCompositedMinProperties,
serdevalid
only.fn validate_composited_min_properties( &self, limit: usize ) -> Result<(), Composited<MinPropertiesError>>
source§impl<T, U> ValidateCompositedMinimum<T> for Nullable<U>where
T: Copy,
U: ValidateCompositedMinimum<T>,
Available on crate feature serdevalid
only.
impl<T, U> ValidateCompositedMinimum<T> for Nullable<U>where T: Copy, U: ValidateCompositedMinimum<T>,
serdevalid
only.fn validate_composited_minimum( &self, limit: T ) -> Result<(), Composited<MinimumError>>
source§impl<T, U> ValidateCompositedMultipleOf<T> for Nullable<U>where
T: Copy,
U: ValidateCompositedMultipleOf<T>,
Available on crate feature serdevalid
only.
impl<T, U> ValidateCompositedMultipleOf<T> for Nullable<U>where T: Copy, U: ValidateCompositedMultipleOf<T>,
serdevalid
only.fn validate_composited_multiple_of( &self, limit: T ) -> Result<(), Composited<MultipleOfError>>
source§impl<T> ValidateCompositedPattern for Nullable<T>where
T: ValidateCompositedPattern,
Available on crate feature serdevalid
only.
impl<T> ValidateCompositedPattern for Nullable<T>where T: ValidateCompositedPattern,
serdevalid
only.fn validate_composited_pattern( &self, limit: &Regex ) -> Result<(), Composited<PatternError>>
impl<T: Copy> Copy for Nullable<T>
impl<T> StructuralPartialEq for Nullable<T>
Auto Trait Implementations§
impl<T> RefUnwindSafe for Nullable<T>where T: RefUnwindSafe,
impl<T> Send for Nullable<T>where T: Send,
impl<T> Sync for Nullable<T>where T: Sync,
impl<T> Unpin for Nullable<T>where T: Unpin,
impl<T> UnwindSafe for Nullable<T>where T: UnwindSafe,
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<Choices> CoproductSubsetter<CNil, HNil> for Choices
impl<Choices> CoproductSubsetter<CNil, HNil> for Choices
source§impl<T> FromJsonReader for Twhere
T: DeserializeOwned + Validate,
impl<T> FromJsonReader for Twhere T: DeserializeOwned + Validate,
source§impl<'de, T> FromJsonSlice<'de> for Twhere
T: Deserialize<'de> + Validate,
impl<'de, T> FromJsonSlice<'de> for Twhere T: Deserialize<'de> + Validate,
source§impl<'de, T> FromJsonStr<'de> for Twhere
T: Deserialize<'de> + Validate,
impl<'de, T> FromJsonStr<'de> for Twhere T: Deserialize<'de> + Validate,
source§impl<T> FromJsonValue for Twhere
T: DeserializeOwned + Validate,
impl<T> FromJsonValue for Twhere T: DeserializeOwned + Validate,
source§fn from_json_value(value: Value) -> Result<T, Error<Error>>
fn from_json_value(value: Value) -> Result<T, Error<Error>>
serde_json::Value
. Read more