Package org.apache.flink.streaming.examples.dsv2.wordcount

Class WordCount.Counter

  • All Implemented Interfaces:
    Serializable, org.apache.flink.api.common.functions.Function, org.apache.flink.datastream.api.function.OneInputStreamProcessFunction<org.apache.flink.api.java.tuple.Tuple2<String,​Integer>,​org.apache.flink.api.java.tuple.Tuple2<String,​Integer>>, org.apache.flink.datastream.api.function.ProcessFunction
    Enclosing class:
    WordCount
    public static final class WordCount.Counter
extends Object
implements org.apache.flink.datastream.api.function.OneInputStreamProcessFunction<org.apache.flink.api.java.tuple.Tuple2<String,​Integer>,​org.apache.flink.api.java.tuple.Tuple2<String,​Integer>>
    Implements a word counter as a user-defined ProcessFunction that counts received words in streaming mode. The function uses a ValueState to store the count of each word, it will update the count of word and output the result when receive a record "(word,1)".

    Note that this is just an example of how to code a streaming job using the DataStream API V2. It currently involves some complexity. In the future, we will provide more user-friendly APIs and extensions to simplify the process.

    See Also:
    Serialized Form

    • Constructor Summary

      Constructors 
      Constructor Description
      Counter()  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void processRecord​(org.apache.flink.api.java.tuple.Tuple2<String,​Integer> record, org.apache.flink.datastream.api.common.Collector<org.apache.flink.api.java.tuple.Tuple2<String,​Integer>> output, org.apache.flink.datastream.api.context.PartitionedContext<org.apache.flink.api.java.tuple.Tuple2<String,​Integer>> ctx)  
      Set<org.apache.flink.api.common.state.StateDeclaration> usesStates()  

      • Methods inherited from interface org.apache.flink.datastream.api.function.OneInputStreamProcessFunction

        endInput, onProcessingTimer, onWatermark, open

      • Methods inherited from interface org.apache.flink.datastream.api.function.ProcessFunction

        close, declareWatermarks

    • Constructor Detail

      • Counter

        public Counter()

    • Method Detail

      • usesStates

        public Set<org.apache.flink.api.common.state.StateDeclaration> usesStates()
        Specified by:
        usesStates in interface org.apache.flink.datastream.api.function.ProcessFunction

      • processRecord

        public void processRecord​(org.apache.flink.api.java.tuple.Tuple2<String,​Integer> record,
                          org.apache.flink.datastream.api.common.Collector<org.apache.flink.api.java.tuple.Tuple2<String,​Integer>> output,
                          org.apache.flink.datastream.api.context.PartitionedContext<org.apache.flink.api.java.tuple.Tuple2<String,​Integer>> ctx)
                   throws Exception
        Specified by:
        processRecord in interface org.apache.flink.datastream.api.function.OneInputStreamProcessFunction<org.apache.flink.api.java.tuple.Tuple2<String,​Integer>,​org.apache.flink.api.java.tuple.Tuple2<String,​Integer>>
        Throws:
        Exception