Package org.apache.flink.streaming.api.functions.windowing

Class ProcessWindowFunction<IN,OUT,KEY,W extends Window>

java.lang.Object

org.apache.flink.api.common.functions.AbstractRichFunction

org.apache.flink.streaming.api.functions.windowing.ProcessWindowFunction<IN,OUT,KEY,W>

Type Parameters:

IN - The type of the input value.

OUT - The type of the output value.

KEY - The type of the key.

W - The type of Window that this window function can be applied on.

All Implemented Interfaces:

Serializable, org.apache.flink.api.common.functions.Function, org.apache.flink.api.common.functions.RichFunction

Direct Known Subclasses:

ReduceApplyProcessWindowFunction

@PublicEvolving
public abstract class ProcessWindowFunction<IN,OUT,KEY,W extends Window>
extends org.apache.flink.api.common.functions.AbstractRichFunction

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

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	ProcessWindowFunction.Context	The context holding window metadata.

Constructor Summary

Constructors

Constructor	Description
ProcessWindowFunction()

Method Summary

Modifier and Type	Method	Description
void	clear(ProcessWindowFunction<IN,OUT,KEY,W>.Context context)	Deletes any state in the Context when the Window expires (the watermark passes its maxTimestamp + allowedLateness).
abstract void	process(KEY key, ProcessWindowFunction<IN,OUT,KEY,W>.Context context, Iterable<IN> elements, org.apache.flink.util.Collector<OUT> out)	Evaluates the window and outputs none or several elements.

Methods inherited from class org.apache.flink.api.common.functions.AbstractRichFunction

close, getIterationRuntimeContext, getRuntimeContext, open, setRuntimeContext

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ProcessWindowFunction

public ProcessWindowFunction()

Method Details

process

public abstract void process(KEY key,
 ProcessWindowFunction<IN,OUT,KEY,W>.Context context,
 Iterable<IN> elements,
 org.apache.flink.util.Collector<OUT> out)
                      throws Exception

Evaluates the window and outputs none or several elements.

Parameters:

key - The key for which this window is evaluated.

context - The context in which the window is being evaluated.

elements - The elements in the window being evaluated.

out - A collector for emitting elements.

Throws:

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

clear

public void clear(ProcessWindowFunction<IN,OUT,KEY,W>.Context context)
           throws Exception

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

Parameters:

context - The context to which the window is being evaluated

Throws:

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