[Ch10c] New code for the new terminal operations section. (f611d5db) · Commits · examples / Head First Java 3rd Edition

src/main/java/ch10c/HelloLambda.java

+12 −1

Changes for src/main/java/ch10c/HelloLambda.java: 12 added lines, 1 removed line.
Original line number	Diff line number	Diff line
		@@ -12,7 +12,7 @@ import java.util.stream.Stream;

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

		static void helloLambda() {
		@@ -48,6 +48,17 @@ public class HelloLambda {
		.collect(Collectors.toList());
		}

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

		List<String> result = strings.stream()
		.sorted((s1, s2) -> s1.compareToIgnoreCase(s2))
		.skip(2)
		.limit(4)
		.collect(Collectors.toList());
		System.out.println("result = " + result);
		}

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

+54 −0

Changes for src/test/java/ch10c/JukeboxQueriesTest.java: 54 added lines, 0 removed lines.
Original line number	Diff line number	Diff line
		@@ -135,6 +135,39 @@ class JukeboxQueriesTest {
		System.out.println("result = " + genreCount);
		}

		@Test
		void shouldSeeIfThereAreAnyRAndBSongs() {
		List<Song> allSongs = songs.getSongs();

		boolean result = allSongs.stream()
		.anyMatch(song -> song.getGenre().equals("R&B"));

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

		@Test
		void shouldFindASong() {
		List<Song> allSongs = songs.getSongs();

		Optional<Song> result = allSongs.stream()
		.filter(song -> song.getYear() == 1995)
		.findFirst();

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

		@Test
		void shouldFindDistinctArtists() {
		List<Song> allSongs = songs.getSongs();

		long result = allSongs.stream()
		.map(Song::getArtist)
		.distinct()
		.count();

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

		// CANDIDATE: exercise 1
		// STRAIGHTFORWARD
		// filter
		@@ -162,6 +195,27 @@ class JukeboxQueriesTest {
		System.out.println("result = " + result);
		}

		// GROUPING
		@Test
		void shouldFindNumberOfTimesSongTitleAppears2() {
		List<Song> allSongs = songs.getSongs();

		Map<String, Long> result = allSongs.stream()
		.collect(Collectors.groupingBy(Song::getTitle, Collectors.counting()));

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

		// GROUPING
		@Test
		void shouldOutputCSVOfArtists() {
		List<Song> songs = this.songs.getSongs();

		System.out.println(songs.stream()
		.map(Song::getArtist)
		.collect(joining(",")));
		}

		// CANDIDATE
		// STRAIGHTFORWARD
		// min terminal