Package org.apache.flink.state.api.functions

Class WindowReaderFunction<IN,OUT,KEY,W extends org.apache.flink.streaming.api.windowing.windows.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, org.apache.flink.api.common.functions.Function, org.apache.flink.api.common.functions.RichFunction
Direct Known Subclasses:
EvictingWindowReaderFunction, PassThroughReader
@PublicEvolving public abstract class WindowReaderFunction<IN,OUT,KEY,W extends org.apache.flink.streaming.api.windowing.windows.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:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static interface 
    WindowReaderFunction.Context<W extends org.apache.flink.streaming.api.windowing.windows.Window>
    The context holding window metadata.

  • Constructor Summary

    Constructors
    Constructor
    Description
    WindowReaderFunction()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    abstract void
    readWindow(KEY key, WindowReaderFunction.Context<W> 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

    • WindowReaderFunction

      public WindowReaderFunction()

  • Method Details

    • readWindow

      public abstract void readWindow(KEY key, WindowReaderFunction.Context<W> 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.