content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   *    http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.spark.examples.ml;
  
  import org.apache.spark.sql.SparkSession;
  
  // $example on$
  import java.util.Arrays;
  import java.util.List;
  
  import org.apache.spark.ml.feature.RFormula;
  import org.apache.spark.sql.Dataset;
  import org.apache.spark.sql.Row;
  import org.apache.spark.sql.RowFactory;
  import org.apache.spark.sql.types.StructField;
  import org.apache.spark.sql.types.StructType;
  
  import static org.apache.spark.sql.types.DataTypes.*;
  // $example off$
  
  public class JavaRFormulaExample {
    public static void main(String[] args) {
      SparkSession spark = SparkSession
        .builder()
        .appName("JavaRFormulaExample")
        .getOrCreate();
  
      // $example on$
      StructType schema = createStructType(new StructField[]{
        createStructField("id", IntegerType, false),
        createStructField("country", StringType, false),
        createStructField("hour", IntegerType, false),
        createStructField("clicked", DoubleType, false)
      });
  
      List<Row> data = Arrays.asList(
        RowFactory.create(7, "US", 18, 1.0),
        RowFactory.create(8, "CA", 12, 0.0),
        RowFactory.create(9, "NZ", 15, 0.0)
      );
  
      Dataset<Row> dataset = spark.createDataFrame(data, schema);
      RFormula formula = new RFormula()
        .setFormula("clicked ~ country + hour")
        .setFeaturesCol("features")
        .setLabelCol("label");
      Dataset<Row> output = formula.fit(dataset).transform(dataset);
      output.select("features", "label").show();
      // $example off$
      spark.stop();
    }
  }
  
  