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* Licensed to the Apache Software Foundation (ASF) under one
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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,
* 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
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*/
package org.apache.cassandra.utils;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import org.apache.cassandra.io.util.DataOutputBuffer;
import org.junit.Before;
import org.junit.Test;
public class BloomFilterTest
{
public BloomFilter bf;
public BloomFilterTest()
{
bf = BloomFilter.getFilter(10000L, FilterTestHelper.MAX_FAILURE_RATE);
}
public static BloomFilter testSerialize(BloomFilter f) throws IOException
{
f.add(ByteBufferUtil.bytes("a"));
DataOutputBuffer out = new DataOutputBuffer();
f.serializer().serialize(f, out);
ByteArrayInputStream in = new ByteArrayInputStream(out.getData(), 0, out.getLength());
BloomFilter f2 = f.serializer().deserialize(new DataInputStream(in));
assert f2.isPresent(ByteBufferUtil.bytes("a"));
assert !f2.isPresent(ByteBufferUtil.bytes("b"));
return f2;
}
@Before
public void clear()
{
bf.clear();
}
@Test(expected = UnsupportedOperationException.class)
public void testBloomLimits1()
{
int maxBuckets = BloomCalculations.probs.length - 1;
int maxK = BloomCalculations.probs[maxBuckets].length - 1;
// possible
BloomCalculations.computeBloomSpec(maxBuckets, BloomCalculations.probs[maxBuckets][maxK]);
// impossible, throws
BloomCalculations.computeBloomSpec(maxBuckets, BloomCalculations.probs[maxBuckets][maxK] / 2);
}
@Test
public void testOne()
{
bf.add(ByteBufferUtil.bytes("a"));
assert bf.isPresent(ByteBufferUtil.bytes("a"));
assert !bf.isPresent(ByteBufferUtil.bytes("b"));
}
@Test
public void testFalsePositivesInt()
{
FilterTestHelper.testFalsePositives(bf, FilterTestHelper.intKeys(), FilterTestHelper.randomKeys2());
}
@Test
public void testFalsePositivesRandom()
{
FilterTestHelper.testFalsePositives(bf, FilterTestHelper.randomKeys(), FilterTestHelper.randomKeys2());
}
@Test
public void testWords()
{
if (KeyGenerator.WordGenerator.WORDS == 0)
{
return;
}
BloomFilter bf2 = BloomFilter.getFilter(KeyGenerator.WordGenerator.WORDS / 2, FilterTestHelper.MAX_FAILURE_RATE);
int skipEven = KeyGenerator.WordGenerator.WORDS % 2 == 0 ? 0 : 2;
FilterTestHelper.testFalsePositives(bf2,
new KeyGenerator.WordGenerator(skipEven, 2),
new KeyGenerator.WordGenerator(1, 2));
}
@Test
public void testSerialize() throws IOException
{
BloomFilterTest.testSerialize(bf);
}
public void testManyHashes(Iterator<ByteBuffer> keys)
{
int MAX_HASH_COUNT = 128;
Set<Long> hashes = new HashSet<Long>();
long collisions = 0;
while (keys.hasNext())
{
hashes.clear();
ByteBuffer buf = keys.next();
for (long hashIndex : BloomFilter.getHashBuckets(buf, MAX_HASH_COUNT, 1024 * 1024))
{
hashes.add(hashIndex);
}
collisions += (MAX_HASH_COUNT - hashes.size());
}
assert collisions <= 100;
}
@Test
public void testManyRandom()
{
testManyHashes(FilterTestHelper.randomKeys());
}
}