Moved PlaylistUtils to default implementations in IPlaylist.

src/main/java/musicplayer/PlayerGUI.java

@@ -9,7 +9,6 @@ import musicplayer.player.IPlayer;
 import musicplayer.playlist.IPlaylist;
 import musicplayer.util.ConfigManager;
 import musicplayer.util.Icons;
-import musicplayer.util.PlaylistUtils;
 import org.jnativehook.GlobalScreen;
 import org.jnativehook.NativeHookException;
 import org.jnativehook.keyboard.NativeKeyEvent;
@@ -263,7 +262,7 @@ public class PlayerGUI extends JPanel implements PlayerCallbackInterface {
                     if (!filename.endsWith(".m3u"))
                         filename += ".m3u";
                     try {
-                        PlaylistUtils.writePlaylistToFile(playlist.getSongList(), new File(filename));
+                        IPlaylist.writePlaylistToFile(playlist.getSongList(), new File(filename));
                     } catch (IOException e1) {
                         JOptionPane.showMessageDialog(null, e1.getMessage() + "\n" + Arrays.toString(e1.getStackTrace()), "Error", JOptionPane.ERROR_MESSAGE);
                     }
@@ -278,7 +277,7 @@ public class PlayerGUI extends JPanel implements PlayerCallbackInterface {
             fileChooser.setDialogType(JFileChooser.OPEN_DIALOG);
             fileChooser.setFileFilter(m3uExtensionFilter);
             if(fileChooser.showOpenDialog(this) == JFileChooser.APPROVE_OPTION){
-                PlaylistUtils.readPlaylistFromFile(fileChooser.getSelectedFile()).stream().forEach(playlist::addSong);
+                IPlaylist.readPlaylistFromFile(fileChooser.getSelectedFile()).stream().forEach(playlist::addSong);
             }
         });
         playlistTools.add(menuItem);

src/main/java/musicplayer/playlist/IPlaylist.java

@@ -1,9 +1,18 @@
 package musicplayer.playlist;
 
+import musicplayer.library.ILibrary;
+import musicplayer.model.Album;
+import musicplayer.model.Artist;
 import musicplayer.model.Song;
 
+import java.io.*;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
+import java.util.stream.Collectors;
 
 public interface IPlaylist {
     void addSong(Song song);
@@ -22,4 +31,48 @@ public interface IPlaylist {
     void setPlayingSong(Song song);
     void setStopped();
 
+    /**
+     * Write a list of songs to a file as an m3u format playlist file.
+     * @param playlist Playlist of songs to write.
+     * @param targetFile File to write playlist into.
+     * @throws IOException
+     */
+    static void writePlaylistToFile(List<Song> playlist, File targetFile) throws IOException {
+        if(!targetFile.exists())
+            targetFile.createNewFile();
+        try (BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(targetFile), "utf-8"))) {
+            writer.write("#EXTM3U\n");
+            for(Song song : playlist){
+                writer.write(song.getM3UFormatString());
+            }
+        }
+    }
+
+    /**
+     * Read songs in from an m3u playlist.
+     * Songs in the playlist with files that don't actually exists will be dropped.
+     * @param targetFile File to read m3u playlist data from.
+     * @return List of songs contained in the playlist.
+     */
+    static List<Song> readPlaylistFromFile(File targetFile){
+        List<Song> result = new ArrayList<>();
+        if(targetFile.exists()){
+            try {
+                List<String> playlistData = Files.lines(targetFile.toPath()).filter(x -> !x.isEmpty() && !x.contains("#EXTINF")).collect(Collectors.toList());
+                if(playlistData.get(0).equals("#EXTM3U")){
+                    playlistData.remove(0);
+                    List<Path> songPaths = playlistData.stream().map(Paths::get).collect(Collectors.toList());
+                    for(int i = 0; i < songPaths.size(); i++){
+                        if(!Files.exists(songPaths.get(i))){ // If song file doesn't exists, try treating it as relative
+                            songPaths.set(i, Paths.get(targetFile.getParent(), songPaths.get(i).toString()));
+                        }
+                    }
+                    songPaths.stream().map(ILibrary::autoParse).filter(Optional::isPresent).map(Optional::get)
+                            .forEach(x -> result.add(new Song(x.getTrackNumber(), x.getDiscNumber(), x.getTitle(), new Artist(x.getArtist()), new Album(x.getAlbum()), x.getGenre(), x.getSongFile())));
+                }
+            } catch (IOException ignored) { }
+        }
+        return result;
+    }
+
 }

src/main/java/musicplayer/util/PlaylistUtils.java

@@ -1,62 +0,0 @@
-package musicplayer.util;
-
-import musicplayer.library.ILibrary;
-import musicplayer.model.Album;
-import musicplayer.model.Artist;
-import musicplayer.model.Song;
-
-import java.io.*;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.nio.file.Paths;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Optional;
-import java.util.stream.Collectors;
-
-public final class PlaylistUtils {
-
-    /**
-     * Write a list of songs to a file as an m3u format playlist file.
-     * @param playlist Playlist of songs to write.
-     * @param targetFile File to write playlist into.
-     * @throws IOException
-     */
-    public static void writePlaylistToFile(List<Song> playlist, File targetFile) throws IOException {
-        if(!targetFile.exists())
-            targetFile.createNewFile();
-        try (BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(targetFile), "utf-8"))) {
-            writer.write("#EXTM3U\n");
-            for(Song song : playlist){
-                writer.write(song.getM3UFormatString());
-            }
-        }
-    }
-
-    /**
-     * Read songs in from an m3u playlist.
-     * Songs in the playlist with files that don't actually exists will be dropped.
-     * @param targetFile File to read m3u playlist data from.
-     * @return List of songs contained in the playlist.
-     */
-    public static List<Song> readPlaylistFromFile(File targetFile){
-        List<Song> result = new ArrayList<>();
-        if(targetFile.exists()){
-            try {
-                List<String> playlistData = Files.lines(targetFile.toPath()).filter(x -> !x.isEmpty() && !x.contains("#EXTINF")).collect(Collectors.toList());
-                if(playlistData.get(0).equals("#EXTM3U")){
-                    playlistData.remove(0);
-                    List<Path> songPaths = playlistData.stream().map(Paths::get).collect(Collectors.toList());
-                    for(int i = 0; i < songPaths.size(); i++){
-                        if(!Files.exists(songPaths.get(i))){ // If song file doesn't exists, try treating it as relative
-                            songPaths.set(i, Paths.get(targetFile.getParent(), songPaths.get(i).toString()));
-                        }
-                    }
-                    songPaths.stream().map(ILibrary::autoParse).filter(Optional::isPresent).map(Optional::get)
-                            .forEach(x -> result.add(new Song(x.getTrackNumber(), x.getDiscNumber(), x.getTitle(), new Artist(x.getArtist()), new Album(x.getAlbum()), x.getGenre(), x.getSongFile())));
-                }
-            } catch (IOException ignored) { }
-        }
-        return result;
-    }
-}

src/test/java/musicplayer/playlist/IPlaylistTest.java

@@ -0,0 +1,31 @@
+package musicplayer.playlist;
+
+import musicplayer.library.ILibrary;
+import musicplayer.model.Song;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.Assert.*;
+
+public class IPlaylistTest {
+
+    @Rule
+    public TemporaryFolder folder = new TemporaryFolder();
+
+    @Test
+    public void testWriteAndReadPlaylist() throws Exception {
+        Song sampleSong = new Song(ILibrary.autoParse(
+                new File(IPlaylistTest.class.getResource("/sample.mp3").getFile()).toPath()).get());
+        File playlistFile = folder.newFile();
+        List<Song> playlist = new ArrayList<>();
+        playlist.add(sampleSong);
+        IPlaylist.writePlaylistToFile(playlist, playlistFile);
+        List<Song> result = IPlaylist.readPlaylistFromFile(playlistFile);
+        assertEquals(sampleSong, result.get(0));
+    }
+}