Close open lines when closing player (fixes #125)

Author: devgianlu

core/src/main/java/xyz/gianlu/librespot/player/LinesHolder.java

@@ -6,13 +6,14 @@
 import xyz.gianlu.librespot.common.Utils;
 
 import javax.sound.sampled.*;
+import java.io.Closeable;
 import java.util.*;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 /**
  * @author Gianlu
  */
-public class LinesHolder {
+public class LinesHolder implements Closeable {
     private static final Logger LOGGER = Logger.getLogger(LinesHolder.class);
     private final Map<Mixer, LineWithState> openLines = new HashMap<>();
 
@@ -67,6 +68,12 @@ public LineWrapper getLineFor(@NotNull Player.Configuration conf, @NotNull Audio
         return getLine(mixer, info);
     }
 
+    @Override
+    public void close() {
+        for (LineWithState line : openLines.values())
+            line.line.close();
+    }
+
     public static class MixerException extends Exception {
         MixerException(String message) {
             super(message);

core/src/main/java/xyz/gianlu/librespot/player/Player.java

@@ -520,6 +520,8 @@ public void close() {
             preloadTrackHandler.close();
             preloadTrackHandler = null;
         }
+
+        lines.close();
     }
 
     @Nullable