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.mllib.feature;
  
  import java.util.Arrays;
  import java.util.List;
  
  import org.junit.Assert;
  import org.junit.Test;
  
  import org.apache.spark.SharedSparkSession;
  import org.apache.spark.api.java.JavaRDD;
  import org.apache.spark.mllib.linalg.Vector;
  
  public class JavaTfIdfSuite extends SharedSparkSession {
  
    @Test
    public void tfIdf() {
      // The tests are to check Java compatibility.
      HashingTF tf = new HashingTF();
      @SuppressWarnings("unchecked")
      JavaRDD<List<String>> documents = jsc.parallelize(Arrays.asList(
        Arrays.asList("this is a sentence".split(" ")),
        Arrays.asList("this is another sentence".split(" ")),
        Arrays.asList("this is still a sentence".split(" "))), 2);
      JavaRDD<Vector> termFreqs = tf.transform(documents);
      termFreqs.collect();
      IDF idf = new IDF();
      JavaRDD<Vector> tfIdfs = idf.fit(termFreqs).transform(termFreqs);
      List<Vector> localTfIdfs = tfIdfs.collect();
      int indexOfThis = tf.indexOf("this");
      for (Vector v : localTfIdfs) {
        Assert.assertEquals(0.0, v.apply(indexOfThis), 1e-15);
      }
    }
  
    @Test
    public void tfIdfMinimumDocumentFrequency() {
      // The tests are to check Java compatibility.
      HashingTF tf = new HashingTF();
      @SuppressWarnings("unchecked")
      JavaRDD<List<String>> documents = jsc.parallelize(Arrays.asList(
        Arrays.asList("this is a sentence".split(" ")),
        Arrays.asList("this is another sentence".split(" ")),
        Arrays.asList("this is still a sentence".split(" "))), 2);
      JavaRDD<Vector> termFreqs = tf.transform(documents);
      termFreqs.collect();
      IDF idf = new IDF(2);
      JavaRDD<Vector> tfIdfs = idf.fit(termFreqs).transform(termFreqs);
      List<Vector> localTfIdfs = tfIdfs.collect();
      int indexOfThis = tf.indexOf("this");
      for (Vector v : localTfIdfs) {
        Assert.assertEquals(0.0, v.apply(indexOfThis), 1e-15);
      }
    }
  
  }
  