src/test/java/org/apache/datasketches/kll/KllItemsSketchiteratorTest.java

/*
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 * 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,
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 * specific language governing permissions and limitations
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package org.apache.datasketches.kll;

import static org.apache.datasketches.quantilescommon.QuantileSearchCriteria.EXCLUSIVE;
import static org.apache.datasketches.quantilescommon.QuantileSearchCriteria.INCLUSIVE;
import static org.testng.Assert.assertEquals;
import static org.testng.Assert.assertTrue;

import java.util.Comparator;

import org.apache.datasketches.common.ArrayOfStringsSerDe;
import org.apache.datasketches.common.Util;
import org.apache.datasketches.quantilescommon.GenericSortedViewIterator;
import org.apache.datasketches.quantilescommon.QuantilesGenericSketchIterator;
import org.testng.Assert;
import org.testng.annotations.Test;

public class KllItemsSketchiteratorTest {
  private ArrayOfStringsSerDe serDe = new ArrayOfStringsSerDe();

  @Test
  public void emptySketch() {
    KllItemsSketch<String> sketch = KllItemsSketch.newHeapInstance(Comparator.naturalOrder(), serDe);
    QuantilesGenericSketchIterator<String> it = sketch.iterator();
    Assert.assertFalse(it.next());
  }

  @Test
  public void oneItemSketch() {
    KllItemsSketch<String> sketch = KllItemsSketch.newHeapInstance(Comparator.naturalOrder(), serDe);
    sketch.update("1");
    QuantilesGenericSketchIterator<String> it = sketch.iterator();
    Assert.assertTrue(it.next());
    Assert.assertEquals(it.getQuantile(), "1");
    Assert.assertEquals(it.getWeight(), 1);
    Assert.assertFalse(it.next());
  }

  @Test
  public void twoItemSketchForIterator() {
    KllItemsSketch<String> sketch = KllItemsSketch.newHeapInstance(Comparator.naturalOrder(), serDe);
    sketch.update("1");
    sketch.update("2");
    QuantilesGenericSketchIterator<String> itr = sketch.iterator();
    assertTrue(itr.next());

    assertEquals(itr.getQuantile(), "2");
    assertEquals(itr.getWeight(), 1);

    assertTrue(itr.next());

    assertEquals(itr.getQuantile(), "1");
    assertEquals(itr.getWeight(), 1);
  }

  @Test
  public void twoItemSketchForSortedViewIterator() {
    KllItemsSketch<String> sketch = KllItemsSketch.newHeapInstance(Comparator.naturalOrder(), serDe);
    sketch.update("1");
    sketch.update("2");
    GenericSortedViewIterator<String> itr = sketch.getSortedView().iterator();

    assertTrue(itr.next());

    assertEquals(itr.getQuantile(), "1");
    assertEquals(itr.getWeight(), 1);
    assertEquals(itr.getCumulativeWeight(EXCLUSIVE), 0);
    assertEquals(itr.getCumulativeWeight(INCLUSIVE), 1);
    assertEquals(itr.getNormalizedRank(EXCLUSIVE), 0);
    assertEquals(itr.getNormalizedRank(INCLUSIVE), 0.5);

    assertTrue(itr.next());

    assertEquals(itr.getQuantile(), "2");
    assertEquals(itr.getWeight(), 1);
    assertEquals(itr.getCumulativeWeight(EXCLUSIVE), 1);
    assertEquals(itr.getCumulativeWeight(INCLUSIVE), 2);
    assertEquals(itr.getNormalizedRank(EXCLUSIVE), 0.5);
    assertEquals(itr.getNormalizedRank(INCLUSIVE), 1.0);
  }

  @Test
  public void bigSketches() {
    final int digits = 6;
    for (int n = 1000; n < 100_000; n += 2000) {
      KllItemsSketch<String> sketch = KllItemsSketch.newHeapInstance(Comparator.naturalOrder(), serDe);
      for (int i = 0; i < n; i++) {
        sketch.update(Util.intToFixedLengthString(i, digits));
      }
      QuantilesGenericSketchIterator<String> it = sketch.iterator();
      int count = 0;
      int weight = 0;
      while (it.next()) {
        count++;
        weight += (int)it.getWeight();
      }
      Assert.assertEquals(count, sketch.getNumRetained());
      Assert.assertEquals(weight, n);
    }
  }

}