Counter.java
/*
* 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.HashMap;
import java.util.Map;
import java.util.stream.Stream;
/**
* Java implementation of Python's collections Counter module.
*
* <p>It counts how many times each element provided occurred in an array and
* returns a map with the element as key and the count as value.</p>
*
* @see <a href="https://docs.python.org/dev/library/collections.html#collections.Counter">
* https://docs.python.org/dev/library/collections.html#collections.Counter</a>
*
* @since 1.0
*/
final class Counter {
/**
* Counts how many times each element provided occurred in an array and
* returns a map with the element as key and the count as value.
*
* @param tokens array of tokens.
* @return a map, where the elements are key, and the count the value.
*/
public static Map<CharSequence, Integer> of(final CharSequence[] tokens) {
final Map<CharSequence, Integer> map = new HashMap<>();
Stream.of(tokens).forEach(token -> map.compute(token, (k, v) -> v != null ? v + 1 : 1));
return map;
}
/**
* Hidden constructor.
*/
private Counter() {
}
}