data and utilities for Lambda/Streams Master Class

MasterClass.java

package masterclass;

import java.util.*;
import java.util.stream.*;
import java.util.Map.Entry;

import static java.util.Map.entry;
import static java.util.stream.Collectors.*;

public class MasterClass {

    // MAIN

    public static void main(String[] args) {
        printMap(alphabetMap);
    }

    // DATA

    public static final List<String> alphabet = List.of(
        "alfa", "bravo", "charlie", "delta", "echo",
        "foxtrot", "golf", "hotel", "india", "juliet",
        "kilo", "lima", "mike", "november", "oscar",
        "papa", "quebec", "romeo", "sierra", "tango",
        "uniform", "victor", "whiskey", "x-ray", "yankee", "zulu");

    public static final List<String> sonnet = List.of(
        "From fairest creatures we desire increase,",
        "That thereby beauty's rose might never die,",
        "But as the riper should by time decease,",
        "His tender heir might bear his memory:",
        "But thou contracted to thine own bright eyes,",
        "Feed'st thy light's flame with self-substantial fuel,",
        "Making a famine where abundance lies,",
        "Thy self thy foe, to thy sweet self too cruel:",
        "Thou that art now the world's fresh ornament,",
        "And only herald to the gaudy spring,",
        "Within thine own bud buriest thy content,",
        "And, tender churl, mak'st waste in niggarding:",
        "Pity the world, or else this glutton be,",
        "To eat the world's due, by the grave and thee.");

    // a = alfa, b = bravo, c = charlie, ...
    public static final Map<String, String> alphabetMap =
        alphabet.stream()
                .collect(toMap(s -> s.substring(0, 1), s -> s));

    // HELPER METHODS

    public static List<String> expand(String s) {
        return s.chars()
                .mapToObj(Character::toString)
                .collect(toList());
    }

    public static void printMap(Map<?,?> map) {
        map.forEach((k, v) -> System.out.printf("%s => %s%n", k, v));
    }
}