Struct datafusion::logical_expr::WindowUDF

pub struct WindowUDF { /* private fields */ }

Logical representation of a user-defined window function (UDWF) A UDWF is different from a UDF in that it is stateful across batches.

See the documetnation on PartitionEvaluator for more details

1. For simple (less performant) use cases, use create_udwf and simple_udwf.rs.

2. For advanced use cases, use WindowUDFImpl and advanced_udwf.rs.

API Note

This is a separate struct from WindowUDFImpl to maintain backwards compatibility with the older API.

Implementations

impl WindowUDF

pub fn new( name: &str, signature: &Signature, return_type: &Arc<dyn Fn(&[DataType]) -> Result<Arc<DataType>, DataFusionError> + Send + Sync>, partition_evaluator_factory: &Arc<dyn Fn() -> Result<Box<dyn PartitionEvaluator>, DataFusionError> + Send + Sync> ) -> WindowUDF

👎Deprecated since 34.0.0: please implement ScalarUDFImpl instead

Create a new WindowUDF from low level details.

See WindowUDFImpl for a more convenient way to create a WindowUDF using trait objects

pub fn new_from_impl<F>(fun: F) -> WindowUDF

where F: WindowUDFImpl + 'static,

Create a new WindowUDF from a [WindowUDFImpl] trait object

Note this is the same as using the From impl (WindowUDF::from)

pub fn inner(&self) -> Arc<dyn WindowUDFImpl>

Return the underlying WindowUDFImpl trait object for this function

pub fn call( &self, args: Vec<Expr>, partition_by: Vec<Expr>, order_by: Vec<Expr>, window_frame: WindowFrame ) -> Expr

creates a Expr that calls the window function given the partition_by, order_by, and window_frame definition

This utility allows using the UDWF without requiring access to the registry, such as with the DataFrame API.

pub fn name(&self) -> &str

Returns this function’s name

See WindowUDFImpl::name for more details.

pub fn signature(&self) -> &Signature

Returns this function’s signature (what input types are accepted)

See WindowUDFImpl::signature for more details.

pub fn return_type( &self, args: &[DataType] ) -> Result<DataType, DataFusionError>

Return the type of the function given its input types

See WindowUDFImpl::return_type for more details.

pub fn partition_evaluator_factory( &self ) -> Result<Box<dyn PartitionEvaluator>, DataFusionError>

Return a PartitionEvaluator for evaluating this window function

Trait Implementations

impl Clone for WindowUDF

fn clone(&self) -> WindowUDF

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for WindowUDF

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

Formats the value using the given formatter.

impl Display for WindowUDF

Defines how the WindowUDF is shown to users

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

Formats the value using the given formatter.

impl<F> From<F> for WindowUDF

where F: WindowUDFImpl + Send + Sync + 'static,

fn from(fun: F) -> WindowUDF

Converts to this type from the input type.

impl Hash for WindowUDF

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

where H: Hasher,

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 PartialEq for WindowUDF

fn eq(&self, other: &WindowUDF) -> 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 Eq for WindowUDF