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put IndexFilter in separate file. 

put BitMapTracker and ArrayTracker back as enclosed classes in
IndexFilter
This commit is contained in:
Claude Warren 2022-06-29 12:41:52 +01:00
parent 8bad223f22
commit 788120b249
7 changed files with 123 additions and 156 deletions
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51
src/main/java/org/apache/commons/collections4/bloomfilter/ArrayTracker.java
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@ -1,51 +0,0 @@
/*
* 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.commons.collections4.bloomfilter;
import java.util.function.IntPredicate;
/**
* An IndexTracker implementation that uses an array of integers to track whether or not a
* number has been seen. Suitable for Shapes that have few hash functions.
* @since 4.5
*/
public class ArrayTracker implements IntPredicate {
private int[] seen;
private int populated;
/**
* Constructs the tracker based on the shape.
* @param shape the shape to build the tracker for.
*/
ArrayTracker(Shape shape) {
seen = new int[shape.getNumberOfHashFunctions()];
}
@Override
public boolean test(int number) {
if (number < 0) {
throw new IndexOutOfBoundsException("number may not be less than zero. " + number);
}
for (int i = 0; i < populated; i++) {
if (seen[i] == number) {
return false;
}
}
seen[populated++] = number;
return true;
}
}

43
src/main/java/org/apache/commons/collections4/bloomfilter/BitMapTracker.java
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@ -1,43 +0,0 @@
/*
* 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.commons.collections4.bloomfilter;
import java.util.function.IntPredicate;
/**
* An IndexTracker implementation that uses an array of bit maps to track whether or not a
* number has been seen.
* @since 4.5
*/
public class BitMapTracker implements IntPredicate {
private long[] bits;
/**
* Constructs a bit map based tracker for the specified shape.
* @param shape The shape that is being generated.
*/
BitMapTracker(Shape shape) {
bits = new long[BitMap.numberOfBitMaps(shape.getNumberOfBits())];
}
@Override
public boolean test(int number) {
boolean retval = !BitMap.contains(bits, number);
BitMap.set(bits, number);
return retval;
}
}

59
src/main/java/org/apache/commons/collections4/bloomfilter/Hasher.java
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@ -55,63 +55,4 @@ public interface Hasher {
* @return the iterator of integers
*/
IndexProducer uniqueIndices(Shape shape);
/**
* A convenience class for Hasher implementations to filter out duplicate indices.
*
* <p><em>If the index is negative the behavior is not defined.</em></p>
*
* <p>This is conceptually a unique filter implemented as a {@code IntPredicate}.</p>
* @since 4.5
*/
final class IndexFilter implements IntPredicate {
private final IntPredicate tracker;
private final int size;
private final IntPredicate consumer;
/**
* Creates an instance optimized for the specified shape.
* @param shape The shape that is being generated.
* @param consumer The consumer to accept the values.
* @return an IndexFilter optimized for the specified shape.
*/
public static IndexFilter create(Shape shape, IntPredicate consumer) {
return new IndexFilter(shape, consumer);
}
/**
* Creates an instance optimized for the specified shape.
* @param shape The shape that is being generated.
* @param consumer The consumer to accept the values.
*/
private IndexFilter(Shape shape, IntPredicate consumer) {
this.size = shape.getNumberOfBits();
this.consumer = consumer;
if (BitMap.numberOfBitMaps(shape.getNumberOfBits()) * Long.BYTES < (long) shape.getNumberOfHashFunctions()
* Integer.BYTES) {
this.tracker = new BitMapTracker(shape);
} else {
this.tracker = new ArrayTracker(shape);
}
}
/**
* Test if the number should be processed by the {@code consumer}.
*
* <p>If the number has <em>not</em> been seen before it is passed to the {@code consumer} and the result returned.
* If the number has been seen before the {@code consumer} is not called and {@code true} returned.</p>
*
* <p><em>If the input is not in the range [0,size) an IndexOutOfBoundsException exception is thrown.</em></p>
*
* @param number the number to check.
* @return {@code true} if processing should continue, {@code false} otherwise.
*/
@Override
public boolean test(int number) {
if (number >= size) {
throw new IndexOutOfBoundsException(String.format("number too large %d >= %d", number, size));
}
return tracker.test(number) ? consumer.test(number) : true;
}
}
}

118
src/main/java/org/apache/commons/collections4/bloomfilter/IndexFilter.java Normal file
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@ -0,0 +1,118 @@
package org.apache.commons.collections4.bloomfilter;
import java.util.function.IntPredicate;
/**
* A convenience class for Hasher implementations to filter out duplicate indices.
*
* <p><em>If the index is negative the behavior is not defined.</em></p>
*
* <p>This is conceptually a unique filter implemented as a {@code IntPredicate}.</p>
* @since 4.5
*/
public final class IndexFilter implements IntPredicate {
private final IntPredicate tracker;
private final int size;
private final IntPredicate consumer;
/**
* Creates an instance optimized for the specified shape.
* @param shape The shape that is being generated.
* @param consumer The consumer to accept the values.
* @return an IndexFilter optimized for the specified shape.
*/
public static IndexFilter create(Shape shape, IntPredicate consumer) {
return new IndexFilter(shape, consumer);
}
/**
* Creates an instance optimized for the specified shape.
* @param shape The shape that is being generated.
* @param consumer The consumer to accept the values.
*/
private IndexFilter(Shape shape, IntPredicate consumer) {
this.size = shape.getNumberOfBits();
this.consumer = consumer;
if (BitMap.numberOfBitMaps(shape.getNumberOfBits()) * Long.BYTES < (long) shape.getNumberOfHashFunctions()
* Integer.BYTES) {
this.tracker = new BitMapTracker(shape);
} else {
this.tracker = new ArrayTracker(shape);
}
}
/**
* Test if the number should be processed by the {@code consumer}.
*
* <p>If the number has <em>not</em> been seen before it is passed to the {@code consumer} and the result returned.
* If the number has been seen before the {@code consumer} is not called and {@code true} returned.</p>
*
* <p><em>If the input is not in the range [0,size) an IndexOutOfBoundsException exception is thrown.</em></p>
*
* @param number the number to check.
* @return {@code true} if processing should continue, {@code false} otherwise.
*/
@Override
public boolean test(int number) {
if (number >= size) {
throw new IndexOutOfBoundsException(String.format("number too large %d >= %d", number, size));
}
return tracker.test(number) ? consumer.test(number) : true;
}
/**
* An IndexTracker implementation that uses an array of integers to track whether or not a
* number has been seen. Suitable for Shapes that have few hash functions.
* @since 4.5
*/
static class ArrayTracker implements IntPredicate {
private int[] seen;
private int populated;
/**
* Constructs the tracker based on the shape.
* @param shape the shape to build the tracker for.
*/
ArrayTracker(Shape shape) {
seen = new int[shape.getNumberOfHashFunctions()];
}
@Override
public boolean test(int number) {
if (number < 0) {
throw new IndexOutOfBoundsException("number may not be less than zero. " + number);
}
for (int i = 0; i < populated; i++) {
if (seen[i] == number) {
return false;
}
}
seen[populated++] = number;
return true;
}
}
/**
* An IndexTracker implementation that uses an array of bit maps to track whether or not a
* number has been seen.
* @since 4.5
*/
static class BitMapTracker implements IntPredicate {
private long[] bits;
/**
* Constructs a bit map based tracker for the specified shape.
* @param shape The shape that is being generated.
*/
BitMapTracker(Shape shape) {
bits = new long[BitMap.numberOfBitMaps(shape.getNumberOfBits())];
}
@Override
public boolean test(int number) {
boolean retval = !BitMap.contains(bits, number);
BitMap.set(bits, number);
return retval;
}
}
}

2
src/test/java/org/apache/commons/collections4/bloomfilter/ArrayTrackerTest.java
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@ -32,7 +32,7 @@ public class ArrayTrackerTest {
@Test
public void testSeen() {
Shape shape = Shape.fromKM(3, 12);
IntPredicate tracker = new ArrayTracker(shape);
IntPredicate tracker = new IndexFilter.ArrayTracker(shape);
assertTrue(tracker.test(0));
assertFalse(tracker.test(0));

2
src/test/java/org/apache/commons/collections4/bloomfilter/BitMapTrackerTest.java
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@ -31,7 +31,7 @@ public class BitMapTrackerTest {
@Test
public void testSeen() {
Shape shape = Shape.fromKM(3, 12);
IntPredicate tracker = new BitMapTracker(shape);
IntPredicate tracker = new IndexFilter.BitMapTracker(shape);
assertTrue(tracker.test(0));
assertFalse(tracker.test(0));

4
src/test/java/org/apache/commons/collections4/bloomfilter/IndexFilterTest.java
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@ -28,7 +28,9 @@ import java.util.List;
import java.util.SplittableRandom;
import java.util.concurrent.ThreadLocalRandom;
import org.apache.commons.collections4.bloomfilter.Hasher.IndexFilter;
import org.apache.commons.collections4.bloomfilter.IndexFilter;
import org.apache.commons.collections4.bloomfilter.IndexFilter.ArrayTracker;
import org.apache.commons.collections4.bloomfilter.IndexFilter.BitMapTracker;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.CsvSource;