/* * Copyright 2023 The original authors * * Licensed 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 dev.morling.onebrc; import java.io.BufferedReader; import java.io.FileNotFoundException; import java.io.FileReader; import java.util.concurrent.ConcurrentSkipListMap; import java.util.stream.Collectors; public class CalculateAverage_naive { record Result(double min, double max, double sum, long count) { } public static void main(String[] args) throws FileNotFoundException { long start = System.currentTimeMillis(); var results = new BufferedReader(new FileReader("./measurements.txt")) .lines() .map(l -> l.split(";")) .collect(Collectors.toMap( parts -> parts[0], parts -> { double temperature = Double.parseDouble(parts[1]); return new Result(temperature, temperature, temperature, 1); }, (oldResult, newResult) -> { double min = Math.min(oldResult.min, newResult.min); double max = Math.max(oldResult.max, newResult.max); double sum = oldResult.sum + newResult.sum; long count = oldResult.count + newResult.count; return new Result(min, max, sum, count); }, ConcurrentSkipListMap::new)); System.out.println(System.currentTimeMillis() - start); System.out.println(results); } }