/*
* 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.cassandra.utils;
import org.junit.Test;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.util.*;
import org.apache.cassandra.io.util.DataOutputBuffer;
import static org.junit.Assert.assertEquals;
public class StreamingHistogramTest
{
@Test
public void testFunction() throws Exception
{
StreamingHistogram hist = new StreamingHistogram(5);
long[] samples = new long[]{23, 19, 10, 16, 36, 2, 9, 32, 30, 45};
// add 7 points to histogram of 5 bins
for (int i = 0; i < 7; i++)
{
hist.update(samples[i]);
}
// should end up (2,1),(9.5,2),(17.5,2),(23,1),(36,1)
Map<Double, Long> expected1 = new LinkedHashMap<Double, Long>(5);
expected1.put(2.0, 1L);
expected1.put(9.5, 2L);
expected1.put(17.5, 2L);
expected1.put(23.0, 1L);
expected1.put(36.0, 1L);
Iterator<Map.Entry<Double, Long>> expectedItr = expected1.entrySet().iterator();
for (Map.Entry<Double, Long> actual : hist.getAsMap().entrySet())
{
Map.Entry<Double, Long> entry = expectedItr.next();
assertEquals(entry.getKey(), actual.getKey(), 0.01);
assertEquals(entry.getValue(), actual.getValue());
}
// merge test
StreamingHistogram hist2 = new StreamingHistogram(3);
for (int i = 7; i < samples.length; i++)
{
hist2.update(samples[i]);
}
hist.merge(hist2);
// should end up (2,1),(9.5,2),(19.33,3),(32.67,3),(45,1)
Map<Double, Long> expected2 = new LinkedHashMap<Double, Long>(5);
expected2.put(2.0, 1L);
expected2.put(9.5, 2L);
expected2.put(19.33, 3L);
expected2.put(32.67, 3L);
expected2.put(45.0, 1L);
expectedItr = expected2.entrySet().iterator();
for (Map.Entry<Double, Long> actual : hist.getAsMap().entrySet())
{
Map.Entry<Double, Long> entry = expectedItr.next();
assertEquals(entry.getKey(), actual.getKey(), 0.01);
assertEquals(entry.getValue(), actual.getValue());
}
// sum test
assertEquals(3.28, hist.sum(15), 0.01);
// sum test (b > max(hist))
assertEquals(10.0, hist.sum(50), 0.01);
}
@Test
public void testSerDe() throws Exception
{
StreamingHistogram hist = new StreamingHistogram(5);
long[] samples = new long[]{23, 19, 10, 16, 36, 2, 9};
// add 7 points to histogram of 5 bins
for (int i = 0; i < samples.length; i++)
{
hist.update(samples[i]);
}
DataOutputBuffer out = new DataOutputBuffer();
StreamingHistogram.serializer.serialize(hist, out);
byte[] bytes = out.toByteArray();
StreamingHistogram deserialized = StreamingHistogram.serializer.deserialize(new DataInputStream(new ByteArrayInputStream(bytes)));
// deserialized histogram should have following values
Map<Double, Long> expected1 = new LinkedHashMap<Double, Long>(5);
expected1.put(2.0, 1L);
expected1.put(9.5, 2L);
expected1.put(17.5, 2L);
expected1.put(23.0, 1L);
expected1.put(36.0, 1L);
Iterator<Map.Entry<Double, Long>> expectedItr = expected1.entrySet().iterator();
for (Map.Entry<Double, Long> actual : deserialized.getAsMap().entrySet())
{
Map.Entry<Double, Long> entry = expectedItr.next();
assertEquals(entry.getKey(), actual.getKey(), 0.01);
assertEquals(entry.getValue(), actual.getValue());
}
}
}