Github user kl0u commented on a diff in the pull request: https://github.com/apache/flink/pull/5481#discussion_r171234411 --- Diff: flink-streaming-java/src/main/java/org/apache/flink/streaming/api/datastream/KeyedStream.java --- @@ -321,19 +324,80 @@ private boolean validateKeyTypeIsHashable(TypeInformation<?> type) { * @param <R> The type of elements emitted by the {@code ProcessFunction}. * * @return The transformed {@link DataStream}. + * + * @deprecated Use {@link KeyedStream#process(KeyedProcessFunction, TypeInformation)} */ + @Deprecated @Override @Internal public <R> SingleOutputStreamOperator<R> process( ProcessFunction<T, R> processFunction, TypeInformation<R> outputType) { - KeyedProcessOperator<KEY, T, R> operator = - new KeyedProcessOperator<>(clean(processFunction)); + LegacyKeyedProcessOperator<K, T, R> operator = new LegacyKeyedProcessOperator<>(clean(processFunction)); return transform("Process", outputType, operator); } + /** + * Applies the given {@link KeyedProcessFunction} on the input stream, thereby creating a transformed output stream. + * + * <p>The function will be called for every element in the input streams and can produce zero + * or more output elements. Contrary to the {@link DataStream#flatMap(FlatMapFunction)} + * function, this function can also query the time and set timers. When reacting to the firing + * of set timers the function can directly emit elements and/or register yet more timers. + * + * @param keyedProcessFunction The {@link KeyedProcessFunction} that is called for each element in the stream. + * + * @param <K> The type of key in {@code KeyedProcessFunction}. + * + * @param <R> The type of elements emitted by the {@code KeyedProcessFunction}. + * + * @return The transformed {@link DataStream}. + */ + @PublicEvolving + public <K, R> SingleOutputStreamOperator<R> process(KeyedProcessFunction<K, T, R> keyedProcessFunction) { + + TypeInformation<R> outType = TypeExtractor.getUnaryOperatorReturnType( + keyedProcessFunction, + KeyedProcessFunction.class, + 0, --- End diff -- The indices here are not `0` and `1` for input and output type, but `1` and `2`. In the process function it was 0 and 1 because we did not have the key.
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