WindowFunction

org.apache.flink.api.function.WindowFunction
@Public
trait WindowFunction[IN, OUT, KEY, W <: Window] extends Function with Serializable

Base interface for functions that are evaluated over keyed (grouped) windows.

Attributes

IN

The type of the input value.

KEY

The type of the key.

OUT

The type of the output value.

Graph
Supertypes
trait Function
trait Serializable
class Object
trait Matchable
class Any
Known subtypes
class RichWindowFunction[IN, OUT, KEY, W]

Members list

Concise view

Value members

Abstract methods

def apply(key: KEY, window: W, input: Iterable[IN], out: Collector[OUT]): Unit

Evaluates the window and outputs none or several elements.

Evaluates the window and outputs none or several elements.

Attributes

input

The elements in the window being evaluated.

key

The key for which this window is evaluated.

out

A collector for emitting elements.

window

The window that is being evaluated.

Throws:
Exception

The function may throw exceptions to fail the program and trigger recovery.