Claudenw commented on a change in pull request #258: URL: https://github.com/apache/commons-collections/pull/258#discussion_r800087782
########## File path: src/main/java/org/apache/commons/collections4/bloomfilter/BitMapProducer.java ########## @@ -0,0 +1,172 @@ +/* + * 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.Arrays; +import java.util.Objects; +import java.util.function.IntPredicate; +import java.util.function.LongPredicate; + +/** + * Produces BitMap longs for a Bloom filter. + * + * Each bit map is a little-endian long value representing a block of bits of this filter. + * + * <p>The returned array will have length {@code ceil(m / 64)} where {@code m} is the + * number of bits in the filter and {@code ceil} is the ceiling function. + * Bits 0-63 are in the first long. A value of 1 at a bit position indicates the bit + * index is enabled. + * + * The producer may stop at the last non zero BitMap or may produce zero value bit maps to the limit determined by + * a shape. + * + * @since 4.5 + */ +public interface BitMapProducer { + + /** + * Each BitMap is passed to the predicate in order. The predicate is applied to each + * bitmap value, if the predicate returns {@code false} the execution is stopped, {@code false} + * is returned, and no further bitmaps are processed. + * + * <p>Any exceptions thrown by the action are relayed to the caller.</p> + * + * @param predicate the function to execute + * @return {@code true} if all bitmaps returned {@code true}, {@code false} otherwise. + * @throws NullPointerException if the specified consumer is null + */ + boolean forEachBitMap(LongPredicate predicate); + + /** + * Creates a BitMapProducer from an array of Long. + * @param bitMaps the bitMaps to return. + * @return a BitMapProducer. + */ + static BitMapProducer fromLongArray(long... bitMaps) { + return new BitMapProducer() { + + @Override + public boolean forEachBitMap(LongPredicate predicate) { + for (long word : bitMaps) { + if (!predicate.test(word)) { + return false; + } + } + return true; + } + + }; + } + + /** + * Creates a BitMapProducer from an IndexProducer. + * @param producer the IndexProducer that specifies the indexes of the bits to enable. + * @param numberOfBits the number of bits in the Bloom filter. + * @return A BitMapProducer that produces the BitMap equivalent of the Indices from the producer. + */ + static BitMapProducer fromIndexProducer(IndexProducer producer, int numberOfBits) { + Objects.requireNonNull(producer, "producer"); + Objects.requireNonNull(numberOfBits, "numberOfBits"); + + return new BitMapProducer() { + private int maxBucket = -1; + private long[] result = new long[BitMap.numberOfBitMaps(numberOfBits)]; + + @Override + public boolean forEachBitMap(LongPredicate predicate) { + Objects.requireNonNull(predicate, "predicate"); + /* + * we can not assume that all the ints will be in order and not repeated. This + * is because the HasherCollection does not make the guarantee. + */ + // process all the ints into a array of BitMaps + IntPredicate builder = new IntPredicate() { + @Override + public boolean test(int i) { + int bucketIdx = BitMap.getLongIndex(i); + maxBucket = maxBucket < bucketIdx ? bucketIdx : maxBucket; + result[bucketIdx] |= BitMap.getLongBit(i); + return true; + } + }; + producer.forEachIndex(builder); + // send the bitmaps to the consumer. + for (int bucket = 0; bucket <= maxBucket; bucket++) { + if (!predicate.test(result[bucket])) { + return false; + } + } + return true; + } + }; + } + + /** + * A LongConsumer that builds an Array of BitMaps as produced by a BitMapProducer. + * + */ + class ArrayBuilder implements LongPredicate { Review comment: Removed the class as it is no longer needed. Functionality is now part of BitMapProducer class as the method `asBitMapArray()` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@commons.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
