Claudenw commented on code in PR #258: URL: https://github.com/apache/commons-collections/pull/258#discussion_r895022534
########## src/main/java/org/apache/commons/collections4/bloomfilter/IndexProducer.java: ########## @@ -0,0 +1,120 @@ +/* + * 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.BitSet; +import java.util.Objects; +import java.util.function.IntPredicate; +import java.util.function.LongPredicate; + +/** + * An object that produces indices of a Bloom filter. + * <p><em> + * The default implementation of {@code asIndexArray} is slow. Implementers should reimplement the + * method where possible.</em></p> + * + * @since 4.5 + */ +@FunctionalInterface +public interface IndexProducer { + + /** + * Each index is passed to the predicate. The predicate is applied to each + * index value, if the predicate returns {@code false} the execution is stopped, {@code false} + * is returned, and no further indices are processed. + * + * <p>Any exceptions thrown by the action are relayed to the caller.</p> + * + * <p>Indices ordering is not guaranteed</p> + * + * @param predicate the action to be performed for each non-zero bit index. + * @return {@code true} if all indexes return true from consumer, {@code false} otherwise. + * @throws NullPointerException if the specified action is null + */ + boolean forEachIndex(IntPredicate predicate); + + /** + * Creates an IndexProducer from an array of integers. + * @param values the index values + * @return an IndexProducer that uses the values. + */ + static IndexProducer fromIndexArray(final int... values) { + return new IndexProducer() { + + @Override + public boolean forEachIndex(IntPredicate predicate) { + for (int value : values) { + if (!predicate.test(value)) { + return false; + } + } + return true; + } + }; + } + + /** + * Creates an IndexProducer from a {@code BitMapProducer}. + * @param producer the {@code BitMapProducer} + * @return a new {@code IndexProducer}. + */ + static IndexProducer fromBitMapProducer(BitMapProducer producer) { + Objects.requireNonNull(producer, "producer"); + return new IndexProducer() { + @Override + public boolean forEachIndex(IntPredicate consumer) { + LongPredicate longPredicate = new LongPredicate() { + int wordIdx = 0; + + @Override + public boolean test(long word) { + int i = wordIdx; + while (word != 0) { + if ((word & 1) == 1) { + if (!consumer.test(i)) { + return false; + } + } + word >>>= 1; + i++; + } + wordIdx += 64; + return true; + } + }; + return producer.forEachBitMap(longPredicate::test); + } + }; + } + + /** + * Return a copy of the IndexProducer data as an int array. + * <p><em> + * The default implementation of this method is slow. It is recommended + * that implementing classes reimplement this method. + * </em></p> + * @return An int array of the data. + */ + default int[] asIndexArray() { Review Comment: created https://issues.apache.org/jira/browse/COLLECTIONS-819 to address this -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
