src/test/java/org/apache/datasketches/tuple/ReadOnlyMemorySegmentTest.java

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 * 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
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 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
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 */

package org.apache.datasketches.tuple;

import java.lang.foreign.MemorySegment;

import org.apache.datasketches.common.SketchesReadOnlyException;
import org.apache.datasketches.tuple.arrayofdoubles.ArrayOfDoublesSetOperationBuilder;
import org.apache.datasketches.tuple.arrayofdoubles.ArrayOfDoublesSketch;
import org.apache.datasketches.tuple.arrayofdoubles.ArrayOfDoublesUnion;
import org.apache.datasketches.tuple.arrayofdoubles.ArrayOfDoublesUpdatableSketch;
import org.apache.datasketches.tuple.arrayofdoubles.ArrayOfDoublesUpdatableSketchBuilder;
import org.testng.Assert;
import org.testng.annotations.Test;

public class ReadOnlyMemorySegmentTest {

  @Test
  public void wrapAndTryUpdatingSketch() {
    final ArrayOfDoublesUpdatableSketch sketch1 = new ArrayOfDoublesUpdatableSketchBuilder().build();
    sketch1.update(1, new double[] {1});
    final ArrayOfDoublesUpdatableSketch sketch2 = (ArrayOfDoublesUpdatableSketch)
        ArrayOfDoublesSketch.wrapSketch(MemorySegment.ofArray(sketch1.toByteArray()));
    Assert.assertEquals(sketch2.getEstimate(), 1.0);
    sketch2.toByteArray();
    boolean thrown = false;
    try {
      sketch2.update(2, new double[] {1});
    } catch (final SketchesReadOnlyException e) {
      thrown = true;
    }
    try {
      sketch2.trim();
    } catch (final SketchesReadOnlyException e) {
      thrown = true;
    }
    Assert.assertTrue(thrown);
  }

  @Test
  public void heapifyAndUpdateSketch() {
    final ArrayOfDoublesUpdatableSketch sketch1 = new ArrayOfDoublesUpdatableSketchBuilder().build();
    sketch1.update(1, new double[] {1});
    // downcasting is not recommended, for testing only
    final ArrayOfDoublesUpdatableSketch sketch2 = (ArrayOfDoublesUpdatableSketch)
        ArrayOfDoublesSketch.heapifySketch(MemorySegment.ofArray(sketch1.toByteArray()));
    sketch2.update(2, new double[] {1});
    Assert.assertEquals(sketch2.getEstimate(), 2.0);
  }

  @Test
  public void wrapAndTryUpdatingUnionEstimationMode() {
    final int numUniques = 10000;
    int key = 0;
    final ArrayOfDoublesUpdatableSketch sketch1 = new ArrayOfDoublesUpdatableSketchBuilder().build();
    for (int i = 0; i < numUniques; i++) {
      sketch1.update(key++, new double[] {1});
    }
    final ArrayOfDoublesUnion union1 = new ArrayOfDoublesSetOperationBuilder().buildUnion();
    union1.union(sketch1);
    final ArrayOfDoublesUnion union2 = ArrayOfDoublesSketch.wrapUnion(MemorySegment.ofArray(union1.toByteArray()).asReadOnly());
    final ArrayOfDoublesSketch resultSketch = union2.getResult();
    Assert.assertTrue(resultSketch.isEstimationMode());
    Assert.assertEquals(resultSketch.getEstimate(), numUniques, numUniques * 0.04);

    // make sure union update actually needs to modify the union
    final ArrayOfDoublesUpdatableSketch sketch2 = new ArrayOfDoublesUpdatableSketchBuilder().build();
    for (int i = 0; i < numUniques; i++) {
      sketch2.update(key++, new double[] {1});
    }

    boolean thrown = false;
    try {
      union2.union(sketch2);
    } catch (final SketchesReadOnlyException e) {
      thrown = true;
    }
    Assert.assertTrue(thrown);
  }

  @Test
  public void heapifyAndUpdateUnion() {
    final int numUniques = 10000;
    int key = 0;
    final ArrayOfDoublesUpdatableSketch sketch1 = new ArrayOfDoublesUpdatableSketchBuilder().build();
    for (int i = 0; i < numUniques; i++) {
      sketch1.update(key++, new double[] {1});
    }
    final ArrayOfDoublesUnion union1 = new ArrayOfDoublesSetOperationBuilder().buildUnion();
    union1.union(sketch1);
    final ArrayOfDoublesUnion union2 = ArrayOfDoublesSketch.heapifyUnion(MemorySegment.ofArray(union1.toByteArray()));
    final ArrayOfDoublesSketch resultSketch = union2.getResult();
    Assert.assertTrue(resultSketch.isEstimationMode());
    Assert.assertEquals(resultSketch.getEstimate(), numUniques, numUniques * 0.04);

    // make sure union update actually needs to modify the union
    final ArrayOfDoublesUpdatableSketch sketch2 = new ArrayOfDoublesUpdatableSketchBuilder().build();
    for (int i = 0; i < numUniques; i++) {
      sketch2.update(key++, new double[] {1});
    }
    union2.union(sketch2);
  }

}