1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.text.similarity; 18 19 import java.util.HashMap; 20 import java.util.Map; 21 import java.util.stream.Stream; 22 23 /** 24 * Java implementation of Python's collections Counter module. 25 * 26 * <p>It counts how many times each element provided occurred in an array and 27 * returns a map with the element as key and the count as value.</p> 28 * 29 * @see <a href="https://docs.python.org/dev/library/collections.html#collections.Counter"> 30 * https://docs.python.org/dev/library/collections.html#collections.Counter</a> 31 * 32 * @since 1.0 33 */ 34 final class Counter { 35 36 /** 37 * Counts how many times each element provided occurred in an array and 38 * returns a map with the element as key and the count as value. 39 * 40 * @param tokens array of tokens. 41 * @return a map, where the elements are key, and the count the value. 42 */ 43 public static Map<CharSequence, Integer> of(final CharSequence[] tokens) { 44 final Map<CharSequence, Integer> map = new HashMap<>(); 45 Stream.of(tokens).forEach(token -> map.compute(token, (k, v) -> v != null ? v + 1 : 1)); 46 return map; 47 } 48 49 /** 50 * Hidden constructor. 51 */ 52 private Counter() { 53 } 54 55 }