org.apache.flink.state.api.functions

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

java.lang.Object

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

org.apache.flink.state.api.functions.WindowReaderFunction<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, Function, RichFunction

Direct Known Subclasses:

EvictingWindowReaderFunction, PassThroughReader

@PublicEvolving
public abstract class WindowReaderFunction<IN,OUT,KEY,W extends Window>
extends 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 and Description
static interface	WindowReaderFunction.Context<W extends Window> The context holding window metadata.

Constructor Summary

Constructors

Constructor and Description
WindowReaderFunction()

Method Summary

Modifier and Type	Method and Description
abstract void	readWindow(KEY key, WindowReaderFunction.Context<W> context, Iterable<IN> elements, 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 Detail

WindowReaderFunction

public WindowReaderFunction()

Method Detail

readWindow

public abstract void readWindow(KEY key,
                                WindowReaderFunction.Context<W> context,
                                Iterable<IN> elements,
                                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.