[Ch10c] Five min mystery; and some playing around for method references (f7c2859a) · Commits · examples / Head First Java 3rd Edition

src/main/java/ch10c/FiveMinMystery.java

0 → 100644

+49 −0

Changes for src/main/java/ch10c/FiveMinMystery.java: 49 added lines, 0 removed lines.
Original line number	Diff line number	Diff line
		package ch10c;

		import java.util.List;
		import java.util.Optional;

		public class FiveMinMystery {
		public static void main(String[] args) {
		List<Coffee> coffees = List.of(new Coffee("Cappuccino", 3),
		new Coffee("Americano", 2), new Coffee("Espresso", 5),
		new Coffee("Cortado", 4), new Coffee("Mocha", 3),
		new Coffee("Flat White", 4), new Coffee("Latte", 3),
		new Coffee("Decaf", 1));

		Optional<String> afternoonCoffee = coffees.stream()
		.map(Coffee::getName)
		.sorted()
		.findFirst();
		System.out.println(afternoonCoffee);
		Optional<String> weakCoffee = coffees.stream()
		.sorted()
		.map(coffee -> coffee.name)
		.findFirst();
		System.out.println(weakCoffee);

		}

		private static class Coffee implements Comparable<Coffee>{
		private final String name;
		private final int strength;

		public Coffee(String name, int strength) {
		this.name = name;
		this.strength = strength;
		}

		public String getName() {
		return name;
		}

		public int getStrength() {
		return strength;
		}

		@Override
		public int compareTo(Coffee other) {
		return this.strength - other.strength;
		}
		}
		}

+11 −1

Changes for src/main/java/ch10c/HelloLambda.java: 11 added lines, 1 removed line.
Original line number	Diff line number	Diff line
		package ch10c;

		import java.util.ArrayList;
		import java.util.Comparator;
		import java.util.List;
		import java.util.concurrent.ExecutorService;
		import java.util.concurrent.Executors;
		@@ -11,7 +12,7 @@ import java.util.stream.Stream;

		public class HelloLambda {
		public static void main(String[] args) {
		mandatoryTypes();
		sortingNaturalOrder();
		}

		static void helloLambda() {
		@@ -26,6 +27,15 @@ public class HelloLambda {
		System.out.println("result = " + result);
		}

		static void sortingNaturalOrder() {
		List<String> strings = List.of("I", "am", "a", "list", "of", "Strings");

		List<String> result = strings.stream()
		.sorted(Comparator.naturalOrder())
		.collect(Collectors.toList());
		System.out.println("result = " + result);
		}

		static void lambdaAsBehaviour() {
		List<String> strings = new ArrayList<>(List.of("I", "am", "a", "list", "of", "Strings"));
		String str = strings.get(2);

+11 −1

Changes for src/test/java/ch10c/JukeboxQueriesTest.java: 11 added lines, 1 removed line.
Original line number	Diff line number	Diff line
		@@ -144,7 +144,7 @@ class JukeboxQueriesTest {
		List<Song> allSongs = songs.getSongs();

		List<Song> result = allSongs.stream()
		.filter(song -> song.getGenre().contains("Rock"))
		.filter(song -> song.getGenre().equals("Rock"))
		.collect(toList());

		System.out.println(result);
		@@ -175,6 +175,16 @@ class JukeboxQueriesTest {
		System.out.println("result = " + result.get());
		}

		@Test
		void shouldOrderBySongAge() {
		List<Song> allSongs = songs.getSongs();
		List<Song> result = allSongs.stream()
		.sorted(Comparator.comparingInt(Song::getYear))
		.collect(toList());

		System.out.println("result = " + result);
		}

		// STRAIGHTFORWARD
		// filter (with param)
		// toList