WindowAssigner (Flink : Streaming Java 1.18.1-cp5 API)

java.lang.Object
- org.apache.flink.streaming.api.windowing.assigners.WindowAssigner<T,W>

Type Parameters:

T - The type of elements that this WindowAssigner can assign windows to.

W - The type of Window that this assigner assigns.

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

GlobalWindows, MergingWindowAssigner, SlidingEventTimeWindows, SlidingProcessingTimeWindows, TumblingEventTimeWindows, TumblingProcessingTimeWindows
```
@PublicEvolving
public abstract class WindowAssigner<T,W extends Window>
extends Object
implements Serializable
```
A WindowAssigner assigns zero or more Windows to an element.
In a window operation, elements are grouped by their key (if available) and by the windows to which it was assigned. The set of elements with the same key and window is called a pane. When a Trigger decides that a certain pane should fire the WindowFunction is applied to produce output elements for that pane.

See Also:

Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`WindowAssigner.WindowAssignerContext`	A context provided to the `WindowAssigner` that allows it to query the current processing time.

Constructor Summary

Constructors
Constructor Description

WindowAssigner()

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`abstract Collection<W>`	`assignWindows(T element, long timestamp, WindowAssigner.WindowAssignerContext context)`	Returns a `Collection` of windows that should be assigned to the element.
`abstract Trigger<T,W>`	`getDefaultTrigger(StreamExecutionEnvironment env)`	Returns the default trigger associated with this `WindowAssigner`.
`abstract org.apache.flink.api.common.typeutils.TypeSerializer<W>`	`getWindowSerializer(org.apache.flink.api.common.ExecutionConfig executionConfig)`	Returns a `TypeSerializer` for serializing windows that are assigned by this `WindowAssigner`.
`abstract boolean`	`isEventTime()`	Returns `true` if elements are assigned to windows based on event time, `false` otherwise.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - WindowAssigner
```
public WindowAssigner()
```
- Method Detail
  - assignWindows
```
public abstract Collection<W> assignWindows(T element,
                                            long timestamp,
                                            WindowAssigner.WindowAssignerContext context)
```
    Returns a Collection of windows that should be assigned to the element.
    
    Parameters:
    
    element - The element to which windows should be assigned.
    
    timestamp - The timestamp of the element.
    
    context - The WindowAssigner.WindowAssignerContext in which the assigner operates.
  - getDefaultTrigger
```
public abstract Trigger<T,W> getDefaultTrigger(StreamExecutionEnvironment env)
```
    Returns the default trigger associated with this WindowAssigner.
  - getWindowSerializer
```
public abstract org.apache.flink.api.common.typeutils.TypeSerializer<W> getWindowSerializer(org.apache.flink.api.common.ExecutionConfig executionConfig)
```
    Returns a TypeSerializer for serializing windows that are assigned by this WindowAssigner.
  - isEventTime
```
public abstract boolean isEventTime()
```
    Returns true if elements are assigned to windows based on event time, false otherwise.