Struct elastic_types::date::DateExpr

pub struct DateExpr<TFormat> { /* fields omitted */ }

A date math expression.

Date math expressions start from an anchor date, like the literal now or 2017-05-06 and apply math operations to produce a new date value.

Examples

A date expression for now plus 2 days:

let expr: DateExpr<BasicDateTime> = DateExpr::now().add_days(2);

Which serialises to:

"now+2d"

A date expression using a concrete date value plus 2 days:

let expr: DateExpr<BasicDateTime> = DateExpr::value(DateValue::now()).add_days(2);

Which serialises to:

"20150301T145500.000Z||+2d"

Methods

impl<TFormat> DateExpr<TFormat> where
    TFormat: DateFormat, 

pub fn now() -> Self

Create a new date expression for now.

This value is different from Date::now() because it doesn't calculate the current date from the system clock. It serialises to the literal string "now", which is interpreted by Elasticsearch when indexing.

pub fn value<TDate>(date: TDate) -> Self where
    TDate: Into<FormattableDateValue<TFormat>>, 

Create a new date expression from a concrete date value.

If the input is a DateValue, then it'll use any format specified on the DateExpr. If the input is a Date or chrono::DateTime, then the format on its mapping must match the format expected by the DateExpr.

Examples

Create a date expression from a chrono::DateTime:

let date = DateValue::now();

// The format annotation `EpochMillis` is required
let expr: DateExpr<EpochMillis> = DateExpr::value(date);

Create a date expression from a Date:

let date: Date<DefaultDateMapping<EpochMillis>> = Date::now();

// The format `EpochMillis` is inferred
let expr = DateExpr::value(date);

Attempting to create a date expression from a Date with a different format will fail to compile:

let date: Date<DefaultDateMapping<BasicDateTime>> = Date::now();

// Error: expected struct `EpochMillis`, found struct `BasicDateTime`
let expr: DateExpr<EpochMillis> = DateExpr::value(date);

This is to ensure formats aren't silently converted when they shouldn't be, leading to runtime errors in Elasticsearch. Convert the date into a DateValue first:

let date: Date<DefaultDateMapping<BasicDateTime>> = Date::now();

let expr: DateExpr<EpochMillis> = DateExpr::value(DateValue::from(date));

pub fn add_years(self, value: usize) -> Self

Add to the anchored date.

pub fn sub_years(self, value: usize) -> Self

Subtract from the anchored date.

pub fn round_year(self) -> Self

Round the anchored date.

pub fn add_months(self, value: usize) -> Self

Add to the anchored date.

pub fn sub_months(self, value: usize) -> Self

Subtract from the anchored date.

pub fn round_month(self) -> Self

Round the anchored date.

pub fn add_weeks(self, value: usize) -> Self

Add to the anchored date.

pub fn sub_weeks(self, value: usize) -> Self

Subtract from the anchored date.

pub fn round_week(self) -> Self

Round the anchored date.

pub fn add_days(self, value: usize) -> Self

Add to the anchored date.

pub fn sub_days(self, value: usize) -> Self

Subtract from the anchored date.

pub fn round_day(self) -> Self

Round the anchored date.

pub fn add_hours(self, value: usize) -> Self

Add to the anchored date.

pub fn sub_hours(self, value: usize) -> Self

Subtract from the anchored date.

pub fn round_hour(self) -> Self

Round the anchored date.

pub fn add_minutes(self, value: usize) -> Self

Add to the anchored date.

pub fn sub_minutes(self, value: usize) -> Self

Subtract from the anchored date.

pub fn round_minute(self) -> Self

Round the anchored date.

pub fn add_seconds(self, value: usize) -> Self

Add to the anchored date.

pub fn sub_seconds(self, value: usize) -> Self

Subtract from the anchored date.

pub fn round_second(self) -> Self

Round the anchored date.

Trait Implementations

impl<TFormat: PartialEq> PartialEq<DateExpr<TFormat>> for DateExpr<TFormat>

fn eq(&self, other: &DateExpr<TFormat>) -> bool

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

fn ne(&self, other: &DateExpr<TFormat>) -> bool

This method tests for !=.

impl<TFormat: Clone> Clone for DateExpr<TFormat>

fn clone(&self) -> DateExpr<TFormat>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<TFormat> Display for DateExpr<TFormat> where
    TFormat: DateFormat, 

fn fmt(&self, f: &mut Formatter) -> FmtResult

Formats the value using the given formatter.

impl<TFormat: Debug> Debug for DateExpr<TFormat>

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

Formats the value using the given formatter.

impl<TFormat> Serialize for DateExpr<TFormat> where
    TFormat: DateFormat, 

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where
    S: Serializer, 

Serialize this value into the given Serde serializer.