[Ch10b] Examples for HashSet, including a Song with equals and hashCode (77075519) · Commits · examples / Head First Java 3rd Edition

src/main/java/ch10b/Jukebox7.java

+2 −3

Changes for src/main/java/ch10b/Jukebox7.java: 2 added lines, 3 removed lines.
Original line number	Diff line number	Diff line
		@@ -4,15 +4,14 @@ import java.util.ArrayList;
		import java.util.List;

		public class Jukebox7 {
		List<SongV4> songList = new ArrayList<>();
		MockMoreSongs mockFile = new MockMoreSongs();
		private final MockMoreSongs mockFile = new MockMoreSongs();

		public static void main(String[] args) {
		new Jukebox7().go();
		}

		public void go() {
		songList = mockFile.getSongs();
		List<SongV3> songList = mockFile.getSongs();
		System.out.println(songList);
		songList.sort((one, two) -> one.getTitle().compareTo(two.getTitle()));
		System.out.println(songList);

0 → 100644

+20 −0

Changes for src/main/java/ch10b/Jukebox8.java: 20 added lines, 0 removed lines.
Original line number	Diff line number	Diff line
		package ch10b;

		import java.util.*;

		public class Jukebox8 {
		private final MockMoreSongs mockFile = new MockMoreSongs();

		public static void main(String[] args) {
		new Jukebox8().go();
		}

		public void go() {
		List<SongV3> songList = mockFile.getSongs();
		System.out.println(songList);
		songList.sort((one, two) -> one.getTitle().compareTo(two.getTitle()));
		System.out.println(songList);
		Set<SongV3> songSet = new HashSet<>(songList);
		System.out.println(songSet);
		}
		}

+18 −9

Changes for src/main/java/ch10b/MockMoreSongs.java: 18 added lines, 9 removed lines.
Original line number	Diff line number	Diff line
		@@ -5,15 +5,24 @@ import java.util.List;

		class MockMoreSongs {

		public List<SongV4> getSongs() {
		List<SongV4> mySongs = new ArrayList<>();
		mySongs.add(new SongV4("somersault", "zero 7", "50"));
		mySongs.add(new SongV4("cassidy", "grateful dead", "65"));
		mySongs.add(new SongV4("$10", "hitchhiker", "80"));
		mySongs.add(new SongV4("havana", "cabello", "60"));
		mySongs.add(new SongV4("$10", "hitchhiker", "80"));
		mySongs.add(new SongV4("Cassidy", "grateful dead", "65"));
		mySongs.add(new SongV4("50 ways", "simon", "70"));
		public List<SongV3> getSongs() {
		List<SongV3> mySongs = new ArrayList<>();
		mySongs.add(new SongV3("somersault", "zero 7", "50"));
		mySongs.add(new SongV3("cassidy", "grateful dead", "65"));
		mySongs.add(new SongV3("$10", "hitchhiker", "80"));
		mySongs.add(new SongV3("havana", "cabello", "60"));
		mySongs.add(new SongV3("$10", "hitchhiker", "80"));
		mySongs.add(new SongV3("cassidy", "grateful dead", "65"));
		mySongs.add(new SongV3("50 ways", "simon", "70"));
		return mySongs;
		}
		}

		// "text file" version
		//somersault, zero 7, 50
		//cassidy, grateful dead, 65
		//$10, hitchhiker, 80
		//havana, cabello, 60
		//$10, hitchhiker, 80
		//cassidy, grateful dead, 65
		//50 ways, simon, 70
		No newline at end of file

+13 −4

Changes for src/main/java/ch10b/SongV4.java: 13 added lines, 4 removed lines.
Original line number	Diff line number	Diff line
		package ch10b;

		public class SongV4 implements Comparable<SongV4> {
		String title;
		String artist;
		String bpm;
		private String title;
		private String artist;
		private String bpm;

		public boolean equals(Object aSong) {
		SongV4 other = (SongV4) aSong;
		return getTitle().equals(other.getTitle());
		}

		public int hashCode() {
		return title.hashCode();
		}

		public int compareTo(SongV4 s) {
		return title.compareTo(s.getTitle());
		@@ -28,6 +37,6 @@ public class SongV4 implements Comparable<SongV4> {
		}

		public String toString() {
		return title + ": " + artist;
		return title;
		}
		}