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.ml.feature;
  
  import java.util.Arrays;
  import java.util.List;
  
  import static org.apache.spark.sql.types.DataTypes.*;
  
  import org.junit.Assert;
  import org.junit.Test;
  
  import org.apache.spark.SharedSparkSession;
  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;
  
  public class JavaStringIndexerSuite extends SharedSparkSession {
  
    @Test
    public void testStringIndexer() {
      StructType schema = createStructType(new StructField[]{
        createStructField("id", IntegerType, false),
        createStructField("label", StringType, false)
      });
      List<Row> data = Arrays.asList(
        cr(0, "a"), cr(1, "b"), cr(2, "c"), cr(3, "a"), cr(4, "a"), cr(5, "c"));
      Dataset<Row> dataset = spark.createDataFrame(data, schema);
  
      StringIndexer indexer = new StringIndexer()
        .setInputCol("label")
        .setOutputCol("labelIndex");
      Dataset<Row> output = indexer.fit(dataset).transform(dataset);
  
      Assert.assertEquals(
        Arrays.asList(cr(0, 0.0), cr(1, 2.0), cr(2, 1.0), cr(3, 0.0), cr(4, 0.0), cr(5, 1.0)),
        output.orderBy("id").select("id", "labelIndex").collectAsList());
    }
  
    /**
     * An alias for RowFactory.create.
     */
    private Row cr(Object... values) {
      return RowFactory.create(values);
    }
  }
  