[GitHub] HeartSaVioR opened a new pull request #23891: [SPARK-26987][SQL] Add a new method to RowFactory: Row with schema

[GitBox <gi...@apache.org>]

HeartSaVioR opened a new pull request #23891: [SPARK-26987][SQL] Add a new method to RowFactory: Row with schema
URL: https://github.com/apache/spark/pull/23891
 
 
   ## What changes were proposed in this pull request?
   
   This patch proposes to expose an official approach for Java API to create a Row with schema.
   
   ## How was this patch tested?
   
   This only exposes the way to leverage existing class in official API, hence no UT added.
   Manually tested against below query:
   
   ```
   SparkSession sparkSession = SparkSession.builder().master("local").getOrCreate();
   StructType inSchema = DataTypes.createStructType(
           new StructField[] {
                   DataTypes.createStructField("id", DataTypes.StringType      , false),
                   DataTypes.createStructField("ts", DataTypes.TimestampType   , false),
                   DataTypes.createStructField("f1", DataTypes.LongType        , true)
           }
   );
   Dataset<Row> rawSet = sparkSession.sqlContext().readStream()
           .format("rate")
           .option("rowsPerSecond", 1)
           .load()
           .map(   (MapFunction<Row, Row>) raw -> {
                       Object[] fields = new Object[3];
                       fields[0] = "id1";
                       fields[1] = raw.getAs("timestamp");
                       fields[2] = raw.getAs("value");
                       return RowFactory.createWithSchema(inSchema, fields);
                   },
                   RowEncoder.apply(inSchema)
           )
           .filter((FilterFunction<Row>) row -> !row.getAs("f1").equals(0L))
           .withWatermark("ts", "10 seconds");
   
   StreamingQuery streamingQuery = rawSet
           .select("*")
           .writeStream()
           .format("console")
           .outputMode("append")
           .start();
   
   try {
       streamingQuery.awaitTermination(30_000);
   } catch (StreamingQueryException e) {
       System.out.println("Caught exception at 'awaitTermination':");
       e.printStackTrace();
   }
   ```
   
   If we change the map function to `return RowFactory.create(fields);`, filter function fails.

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