Adds a proper GUI to display backup progress

Extracts backup code to its own class
Adds a new GUI to display progress and the file copied

src/main/java/net/knarcraft/minecraftserverlauncher/userinterface/BackupGUI.java

@@ -0,0 +1,94 @@
+package net.knarcraft.minecraftserverlauncher.userinterface;
+
+import net.knarcraft.minecraftserverlauncher.utility.BackupUtil;
+
+import javax.swing.*;
+import java.awt.*;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+/**
+ * The Backup GUI is used to display backup progress
+ */
+public class BackupGUI implements ActionListener {
+    private static JFrame frame;
+    private static JTextArea progressTextArea;
+    private static JProgressBar progressBar;
+    private static JButton cancelButton;
+
+    /**
+     * Instantiates a new GUI
+     */
+    public BackupGUI() {
+        instantiate();
+    }
+
+    /**
+     * Initializes the server consoles frame
+     */
+    public void instantiate() {
+        if (frame != null) {
+            return;
+        }
+        frame = new JFrame("Running backup...");
+        frame.setBounds(100, 100, 500, 140);
+        frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
+        progressTextArea = new JTextArea();
+        progressTextArea.setEditable(false);
+        progressBar = new JProgressBar();
+        cancelButton = new JButton("Cancel");
+        JPanel panel = new JPanel();
+        panel.setLayout(new BoxLayout(panel, BoxLayout.PAGE_AXIS));
+        panel.add(progressTextArea);
+        panel.add(Box.createRigidArea(new Dimension(0,5)));
+        panel.add(progressBar);
+
+        JPanel buttonPane = new JPanel();
+        buttonPane.setLayout(new BoxLayout(buttonPane, BoxLayout.LINE_AXIS));
+        buttonPane.setBorder(BorderFactory.createEmptyBorder(0, 10, 10, 10));
+        buttonPane.add(Box.createHorizontalGlue());
+        buttonPane.add(cancelButton);
+        cancelButton.addActionListener(BackupGUI.this);
+
+        panel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
+        Container contentPane = frame.getContentPane();
+        contentPane.add(panel, BorderLayout.CENTER);
+        contentPane.add(buttonPane, BorderLayout.PAGE_END);
+        frame.setVisible(true);
+    }
+
+    /**
+     * Updates information about the backup progress
+     *
+     * @param infoText <p>The text to display</p>
+     * @param progressPercent <p>The new percent of the progress bar</p>
+     */
+    public static void updateProgress(String infoText, int progressPercent) {
+        if (progressTextArea == null || progressBar == null) {
+            return;
+        }
+        progressTextArea.setText(infoText);
+        progressBar.setValue(progressPercent);
+    }
+
+    /**
+     * Destroys the backup GUI
+     */
+    public static void destroy() {
+        BackupUtil.abortBackup();
+        progressTextArea = null;
+        progressBar = null;
+        cancelButton = null;
+        if (frame != null) {
+            frame.dispose();
+        }
+        frame = null;
+    }
+
+    @Override
+    public void actionPerformed(ActionEvent actionEvent) {
+        if (actionEvent.getSource() == cancelButton) {
+            destroy();
+        }
+    }
+}

src/main/java/net/knarcraft/minecraftserverlauncher/userinterface/ServerLauncherGUI.java

@@ -4,7 +4,7 @@ import net.knarcraft.minecraftserverlauncher.Main;
 import net.knarcraft.minecraftserverlauncher.profile.Collection;
 import net.knarcraft.minecraftserverlauncher.profile.ServerLauncherController;
 import net.knarcraft.minecraftserverlauncher.server.ServerHandler;
-import net.knarcraft.minecraftserverlauncher.utility.CommonFunctions;
+import net.knarcraft.minecraftserverlauncher.utility.BackupUtil;
 
 import javax.imageio.ImageIO;
 import javax.naming.ConfigurationException;
@@ -334,7 +334,7 @@ public class ServerLauncherGUI extends MessageHandler implements ActionListener,
             addServer();
         } else if (actionSource == backupButton) {
             //Run backup in its own thread to prevent locking up
-            Executors.newSingleThreadExecutor().execute(() -> CommonFunctions.backup(this));
+            Executors.newSingleThreadExecutor().execute(() -> BackupUtil.backup(this));
         } else if (actionSource == addProfileButton) {
             controller.addProfile(JOptionPane.showInputDialog("Profile name: "));
             updateProfiles();