[Ch10c] Some example queries (e04c0a13) · Commits · examples / Head First Java 3rd Edition

src/test/java/ch10c/JukeboxQueriesTest.java

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Changes for src/test/java/ch10c/JukeboxQueriesTest.java: 106 added lines, 0 removed lines.
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		package ch10c;

		import org.junit.jupiter.api.BeforeEach;
		import org.junit.jupiter.api.Test;

		import java.util.*;
		import java.util.function.Function;
		import java.util.stream.Collectors;

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

		class JukeboxQueriesTest {
		private JukeboxData.Songs songs;

		@BeforeEach
		void setUp() {
		songs = new JukeboxData.Songs();
		}

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

		System.out.println(allSongs);
		}

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

		List<Song> result = allSongs.stream()
		.sorted(Comparator.comparingInt(Song::getTimesPlayed))
		.collect(Collectors.toList());

		System.out.println(result);
		}

		@Test
		void shouldQueryForGenre() {
		List<Song> allSongs = songs.getSongs();
		// ORDER MATTERS
		List<String> genres = allSongs.stream().map(song -> song.getGenre())
		.distinct()
		.collect(toList());
		System.out.println("genres = " + genres);

		System.out.println(allSongs.stream().map(song -> song.getGenre())
		.distinct()
		.count());

		Map<String, Long> genreCount = allSongs.stream().map(song -> song.getGenre())
		.collect(groupingBy(Function.identity(), counting()));
		System.out.println("genreCount = " + genreCount);
		}

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

		Optional<Song> result = allSongs.stream()
		.max(Comparator.comparingInt(Song::getTimesPlayed));

		System.out.println(result.get());
		}

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

		HashMap<String, Integer> genreCount = new HashMap<>();

		for (Song song : allSongs) {
		int timesPlayed = song.getTimesPlayed();
		String genre = song.getGenre();
		if (genreCount.get(genre) == null) {
		genreCount.put(genre, timesPlayed);
		} else {
		Integer integer = genreCount.get(genre);
		genreCount.put(genre, integer + timesPlayed);
		}
		}
		System.out.println("result = " + genreCount);
		}

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

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

		System.out.println(result);
		}

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

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

		System.out.println("result = " + result);
		}
		}
		No newline at end of file

src/test/java/ch10c/JukeboxV3Test.java

deleted100644 → 0

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Changes for src/test/java/ch10c/JukeboxV3Test.java: 0 added lines, 37 removed lines.
Original line number	Diff line number	Diff line
		package ch10c;

		import org.junit.jupiter.api.BeforeEach;
		import org.junit.jupiter.api.Test;

		import java.util.Comparator;
		import java.util.List;
		import java.util.stream.Collectors;

		class JukeboxV3Test {
		private JukeboxData.Songs songs;

		@BeforeEach
		void setUp() {
		songs = new JukeboxData.Songs();
		}

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

		System.out.println(allSongs);
		}

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

		List<Song> result = allSongs.stream()
		.sorted(Comparator.comparingInt(Song::getTimesPlayed))
		.collect(Collectors.toList());

		System.out.println(result);
		}


		}
		No newline at end of file