aherbert commented on a change in pull request #109: TEXT-155: Add a generic IntersectionSimilarity measure URL: https://github.com/apache/commons-text/pull/109#discussion_r263996968
########## File path: src/main/java/org/apache/commons/text/similarity/IntersectionSimilarity.java ########## @@ -0,0 +1,197 @@ +/* + * 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.text.similarity; + +import java.util.Collection; +import java.util.HashMap; +import java.util.Map; +import java.util.Set; +import java.util.function.Function; +import java.util.stream.Stream; + +/** + * Measures the intersection of two sets created from a pair of character sequences. + * + * <p>It is assumed that the type {@code T} correctly conforms to the requirements for storage + * within a {@link Set} or {@link HashMap}. Ideally the type is immutable and implements + * {@link Object#equals(Object)} and {@link Object#hashCode()}.</p> + * + * @param <T> the type of the elements extracted from the character sequence + * @since 1.7 + * @see Set + * @see HashMap + */ +public class IntersectionSimilarity<T> implements SimilarityScore<IntersectionResult> { + /** The converter used to create the elements from the characters. */ + private final Function<CharSequence, Collection<T>> converter; + + // The following is adapted from commons-collections for a Bag. + // A Bag is a collection that can store the count of the number + // of copies of each element. Review comment: Yes. But once I got going I found the amount of code was minimal. This implementation is faster as it does not support fail-fast concurrent modification checking for threads and doesn't even know it's own size (saving unneeded counter incrementation). I'd favour not adding a dependency just for this 15 lines of code and using the faster implementation. However if we do use `Bag` from collections it offers the possibility that the user can pass one in (via the converter function) and the algorithm detects it. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
