pl.prutkowski.java.playground.java8.TestCollectors.java Source code

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Here is the source code for pl.prutkowski.java.playground.java8.TestCollectors.java

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package pl.prutkowski.java.playground.java8;

import org.apache.commons.lang3.StringUtils;
import pl.prutkowski.java.playground.java8.domain.ListCollector;

import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

/**
 *
 * @author ruter
 */
public class TestCollectors {

    static List<String> months = Arrays.asList("stycze", "luty", "marzec", "kwiecie", "maj", "czerwiec",
            "lipiec", "sierpie", "wrzesie", "padziernik", "listopad", "grudzie");

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Map<String, Integer> monthByLen = months.stream()
                .collect(Collectors.toMap(String::toUpperCase, m -> StringUtils.countMatches(m, "e")));

        monthByLen.forEach((month, eCount) -> System.out.println(month + " -> " + eCount));

        System.out.println("---------------------------------");

        Map<Object, List<String>> monthByLen2 = months.stream()
                .collect(Collectors.groupingBy(m -> StringUtils.countMatches(m, "e")));

        monthByLen2.forEach((count, groupedMonths) -> System.out.println(count + " -> " + groupedMonths));

        System.out.println("---------------------------------");

        Double averageLength = months.stream().collect(Collectors.averagingDouble(String::length));
        System.out.println("Average length: " + averageLength);
        System.out.println("---------------------------------");

        Double max = months.stream().collect(Collectors.summarizingDouble(String::length)).getMax();
        System.out.println("Max length: " + max);
        System.out.println("---------------------------------");

        String reduced = months.stream().collect(Collectors.reducing((m1, m2) -> (m1 + ", " + m2))).get();
        System.out.println("Reduced: " + reduced);
        System.out.println("---------------------------------");
        System.out.println(String.join(", ", months));
        System.out.println("---------------------------------");

        List<String> monthsWithZ = months.stream().filter(m -> m.contains("z")).collect(new ListCollector<>());
        System.out.println(monthsWithZ);

    }

}