Package org.apache.flink.state.api

Class KeyedStateTransformation<K,T>

java.lang.Object
org.apache.flink.state.api.KeyedStateTransformation<K,T>
Type Parameters:
K - The type of the key in the Keyed OperatorTransformation.
T - The type of the elements in the Keyed OperatorTransformation.
@PublicEvolving public class KeyedStateTransformation<K,T> extends Object
A KeyedStateTransformation represents a OneInputStateTransformation on which operator state is partitioned by key using a provided KeySelector.

  • Method Details

    • transform

      public StateBootstrapTransformation<T> transform(KeyedStateBootstrapFunction<K,T> processFunction)
      Applies the given KeyedStateBootstrapFunction on the keyed input.

      The function will be called for every element in the input and can be used for writing both keyed and operator state into a Savepoint.

      Parameters:
      processFunction - The KeyedStateBootstrapFunction that is called for each element.
      Returns:
      An StateBootstrapTransformation that can be added to a Savepoint.

    • transform

      public StateBootstrapTransformation<T> transform(SavepointWriterOperatorFactory factory)
      Method for passing user defined operators along with the type information that will transform the OperatorTransformation.

      IMPORTANT: Any output from this operator will be discarded.

      Parameters:
      factory - A factory returning transformation logic type of the return stream
      Returns:
      An StateBootstrapTransformation that can be added to a Savepoint.

    • window

      public <W extends org.apache.flink.streaming.api.windowing.windows.Window> WindowedStateTransformation<T,K,W> window(org.apache.flink.streaming.api.windowing.assigners.WindowAssigner<? super T,W> assigner)
      Windows this transformation into a WindowedOperatorTransformation, which bootstraps state that can be restored by a WindowOperator. Elements are put into windows by a WindowAssigner. The grouping of elements is done both by key and by window.

      A Trigger can be defined to specify when windows are evaluated. However, WindowAssigners have a default Trigger that is used if a Trigger is not specified.

      Parameters:
      assigner - The WindowAssigner that assigns elements to windows.