Package org.apache.flink.streaming.api.datastream

Class DataStreamUtils

  • @Experimental
public final class DataStreamUtils
extends Object
    A collection of utilities for DataStreams.

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static <T,​K>
      org.apache.flink.streaming.api.datastream.KeyedStream<T,​K>      		 reinterpretAsKeyedStream​(org.apache.flink.streaming.api.datastream.DataStream<T> stream, org.apache.flink.api.java.functions.KeySelector<T,​K> keySelector)
      Reinterprets the given DataStream as a KeyedStream, which extracts keys with the given KeySelector.
      static <T,​K>
      org.apache.flink.streaming.api.datastream.KeyedStream<T,​K>      		 reinterpretAsKeyedStream​(org.apache.flink.streaming.api.datastream.DataStream<T> stream, org.apache.flink.api.java.functions.KeySelector<T,​K> keySelector, org.apache.flink.api.common.typeinfo.TypeInformation<K> typeInfo)
      Reinterprets the given DataStream as a KeyedStream, which extracts keys with the given KeySelector.

    • Method Detail

      • reinterpretAsKeyedStream

        public static <T,​K> org.apache.flink.streaming.api.datastream.KeyedStream<T,​K> reinterpretAsKeyedStream​(org.apache.flink.streaming.api.datastream.DataStream<T> stream,
                                                                                                                    org.apache.flink.api.java.functions.KeySelector<T,​K> keySelector)
        Reinterprets the given DataStream as a KeyedStream, which extracts keys with the given KeySelector.

        IMPORTANT: For every partition of the base stream, the keys of events in the base stream must be partitioned exactly in the same way as if it was created through a DataStream.keyBy(KeySelector).

        Type Parameters:
        T - Type of events in the data stream.
        K - Type of the extracted keys.
        Parameters:
        stream - The data stream to reinterpret. For every partition, this stream must be partitioned exactly in the same way as if it was created through a DataStream.keyBy(KeySelector).
        keySelector - Function that defines how keys are extracted from the data stream.
        Returns:
        The reinterpretation of the DataStream as a KeyedStream.

      • reinterpretAsKeyedStream

        public static <T,​K> org.apache.flink.streaming.api.datastream.KeyedStream<T,​K> reinterpretAsKeyedStream​(org.apache.flink.streaming.api.datastream.DataStream<T> stream,
                                                                                                                    org.apache.flink.api.java.functions.KeySelector<T,​K> keySelector,
                                                                                                                    org.apache.flink.api.common.typeinfo.TypeInformation<K> typeInfo)
        Reinterprets the given DataStream as a KeyedStream, which extracts keys with the given KeySelector.

        IMPORTANT: For every partition of the base stream, the keys of events in the base stream must be partitioned exactly in the same way as if it was created through a DataStream.keyBy(KeySelector).

        Type Parameters:
        T - Type of events in the data stream.
        K - Type of the extracted keys.
        Parameters:
        stream - The data stream to reinterpret. For every partition, this stream must be partitioned exactly in the same way as if it was created through a DataStream.keyBy(KeySelector).
        keySelector - Function that defines how keys are extracted from the data stream.
        typeInfo - Explicit type information about the key type.
        Returns:
        The reinterpretation of the DataStream as a KeyedStream.