Added global keyboard controls/

pom.xml

@@ -85,6 +85,11 @@
             <artifactId>junit</artifactId>
             <version>4.12</version>
         </dependency>
+        <dependency>
+            <groupId>lc.kra.system</groupId>
+            <artifactId>system-hook</artifactId>
+            <version>2.1</version>
+        </dependency>
     </dependencies>
 
     <repositories>
@@ -97,6 +102,14 @@
             <id>jaudiotagger-repository</id>
             <url>https://dl.bintray.com/ijabz/maven</url>
         </repository>
+        <repository>
+            <id>system-hook-mvn-repo</id>
+            <url>https://raw.github.com/kristian/system-hook/mvn-repo/</url>
+            <snapshots>
+                <enabled>true</enabled>
+                <updatePolicy>always</updatePolicy>
+            </snapshots>
+        </repository>
     </repositories>
 
 </project>

src/main/java/musicplayer/PlayerGUI.java

@@ -1,5 +1,8 @@
 package musicplayer;
 
+import lc.kra.system.keyboard.GlobalKeyboardHook;
+import lc.kra.system.keyboard.event.GlobalKeyAdapter;
+import lc.kra.system.keyboard.event.GlobalKeyEvent;
 import musicplayer.callbacks.LibraryCallbackInterface;
 import musicplayer.callbacks.PlayerCallbackInterface;
 import musicplayer.db.DatabaseManager;
@@ -14,10 +17,7 @@ import javax.swing.tree.DefaultMutableTreeNode;
 import javax.swing.tree.DefaultTreeModel;
 import javax.swing.tree.TreeNode;
 import java.awt.*;
-import java.awt.event.ItemEvent;
-import java.awt.event.MouseAdapter;
-import java.awt.event.MouseEvent;
-import java.awt.event.MouseListener;
+import java.awt.event.*;
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Path;
@@ -55,6 +55,8 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
             }
         }, "seekbar");
         seekBarUpdater.start();
+        GlobalKeyboardHook keyboardHook = new GlobalKeyboardHook();
+        keyboardHook.addKeyListener(new GlobalKeyboardShortcuts());
         refreshLibrary();
     }
 
@@ -499,4 +501,49 @@ public class PlayerGUI implements PlayerCallbackInterface, LibraryCallbackInterf
         @Override
         public void mouseExited(MouseEvent e) {}
     }
+
+    private class GlobalKeyboardShortcuts extends GlobalKeyAdapter {
+        final int modifierKey = 93;
+        final int playPause = 116;
+        final int stop = 117;
+        final int previous = 118;
+        final int next = 119;
+        boolean modified = false;
+
+        @Override
+        public void keyPressed(GlobalKeyEvent event) {
+            if(event.getVirtualKeyCode() == modifierKey)
+                modified = true;
+            else if(modified){
+                switch(event.getVirtualKeyCode()){
+                    case playPause:
+                        if(player.isPlaying()){
+                            player.pause();
+                            setSongHighlighting(player.getCurrentSong()); // Resume won't function if a different song is selected.
+                        }
+                        else{
+                            if (playList.getRowCount() > 0) {
+                                if (playList.getSelectedRowCount() > 0)
+                                    player.playSong(playlistTableModel.getSong(playList.getSelectedRow()));
+                                else
+                                    player.playSong(playlistTableModel.getFirst());
+                            }
+                        }
+                        break;
+                    case stop:
+                        player.stop(); break;
+                    case previous:
+                        playPreviousSong(); break;
+                    case next:
+                        playNextSong(); break;
+                }
+            }
+        }
+
+        @Override
+        public void keyReleased(GlobalKeyEvent event) {
+            if(event.getVirtualKeyCode() == modifierKey)
+                modified = false;
+        }
+    }
 }