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/*
* 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.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.DoubleSummaryStatistics;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import static java.util.stream.Collectors.groupingBy;
public class CalculateAverage_khmarbaise {
private static final Path MEASUREMENT_FILES = Path.of("./measurements.txt");
private record MeasurementRecord(String city, Double measuredValue) {
}
private static final Function<String, MeasurementRecord> toMeasurementRecord = line -> {
var posOf = line.indexOf(";");
var city = line.substring(0, posOf);
var measuredValue = line.substring(posOf + 1);
return new MeasurementRecord(city, Double.parseDouble(measuredValue));
};
private static final Function<Map.Entry<String, DoubleSummaryStatistics>, String> MIN_AVG_MAX = s -> String.format("%s=%.1f/%.1f/%.1f", s.getKey(),
s.getValue().getMin(), s.getValue().getAverage(), s.getValue().getMax());
public static void main(String[] args) throws IOException {
try (Stream<String> lines = Files.lines(MEASUREMENT_FILES)) {
var collect = lines
.parallel()
.map(toMeasurementRecord)
.collect(groupingBy(MeasurementRecord::city, Collectors.summarizingDouble(MeasurementRecord::measuredValue)))
.entrySet()
.stream()
.sorted(Map.Entry.comparingByKey())
.map(MIN_AVG_MAX)
.collect(Collectors.joining(", "));
System.out.println("{" + collect + "}");
}
}
}
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