ProcessWindowFunction

org.apache.flink.api.function.ProcessWindowFunction

@PublicEvolving

abstract class ProcessWindowFunction[IN, OUT, KEY, W <: Window] extends AbstractRichFunction

Base abstract class for functions that are evaluated over keyed (grouped) windows using a context for retrieving extra information.

Attributes

IN: The type of the input value.
KEY: The type of the key.
OUT: The type of the output value.
W: The type of the window.
Graph
Supertypes: class AbstractRichFunction
trait RichFunction
trait Function
trait Serializable
class Object
trait Matchable
class Any

Concise view

The context holding window metadata

Evaluates the window and outputs none or several elements.

context: The context in which the window is being evaluated.
elements: The elements in the window being evaluated.
key: The key for which this window is evaluated.
out: A collector for emitting elements.
Throws:: Exception
The function may throw exceptions to fail the program and trigger recovery.

Deletes any state in the Context when the Window expires (the watermark passes its maxTimestamp + allowedLateness).

context: The context to which the window is being evaluated
Throws:: Exception
The function may throw exceptions to fail the program and trigger recovery.

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