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 edu.emory.mathcs.jtransforms.dct.DoubleDCT_1D;
  
  import org.junit.Assert;
  import org.junit.Test;
  
  import org.apache.spark.SharedSparkSession;
  import org.apache.spark.ml.linalg.Vector;
  import org.apache.spark.ml.linalg.VectorUDT;
  import org.apache.spark.ml.linalg.Vectors;
  import org.apache.spark.sql.Dataset;
  import org.apache.spark.sql.Row;
  import org.apache.spark.sql.RowFactory;
  import org.apache.spark.sql.types.Metadata;
  import org.apache.spark.sql.types.StructField;
  import org.apache.spark.sql.types.StructType;
  
  public class JavaDCTSuite extends SharedSparkSession {
  
    @Test
    public void javaCompatibilityTest() {
      double[] input = new double[]{1D, 2D, 3D, 4D};
      Dataset<Row> dataset = spark.createDataFrame(
        Arrays.asList(RowFactory.create(Vectors.dense(input))),
        new StructType(new StructField[]{
          new StructField("vec", (new VectorUDT()), false, Metadata.empty())
        }));
  
      double[] expectedResult = input.clone();
      (new DoubleDCT_1D(input.length)).forward(expectedResult, true);
  
      DCT dct = new DCT()
        .setInputCol("vec")
        .setOutputCol("resultVec");
  
      List<Row> result = dct.transform(dataset).select("resultVec").collectAsList();
      Vector resultVec = result.get(0).getAs("resultVec");
  
      Assert.assertArrayEquals(expectedResult, resultVec.toArray(), 1e-6);
    }
  }
  