Implemented main functionality

src/main/java/org/lalber/tools/exifrotation/Main.java

@@ -0,0 +1,83 @@
+package org.lalber.tools.exifrotation;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import javax.swing.*;
+import javax.swing.border.EtchedBorder;
+import javax.swing.border.TitledBorder;
+import javaxt.io.Image;
+
+/**
+ * @author Lucas Alber
+ */
+public class Main {
+
+    /**
+     * Main entry point to application.
+     *
+     * @param args not used.
+     */
+    public static void main(String[] args) {
+        File folder = showFileSelectionDialog();
+        if (folder == null) return;
+
+        JPanel mainPanel = new JPanel();
+        mainPanel.setBorder(new TitledBorder(new EtchedBorder(), "Process:"));
+
+        JTextArea textArea = new JTextArea(16, 58);
+        textArea.setEditable(false);
+        JScrollPane scroll = new JScrollPane(textArea);
+        scroll.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
+
+        mainPanel.add(scroll);
+
+        JFrame frame = new JFrame();
+        frame.setTitle("Exif Image-Rotation Tool");
+        frame.add(mainPanel);
+        frame.pack();
+        frame.setLocationRelativeTo(null);
+        frame.setVisible(true);
+
+        try {
+            Files.walk(folder.toPath())
+                    .filter(Main::isImage)
+                    .forEach(p -> {
+                        textArea.append("Processing: " + p.getFileName().toString() + "\n");
+                        Image img = new Image(p.toFile());
+                        img.rotate();
+                        img.saveAs(p.toFile());
+                    });
+
+        } catch (IOException e) {
+            System.err.println("Error processing images!");
+            e.printStackTrace();
+        }
+
+        textArea.append("FINISHED!");
+    }
+
+    /**
+     * Shows a Dialog to choose a Directory.
+     * @return the directory or null if the dialog was closed
+     */
+    private static File showFileSelectionDialog() {
+        JFileChooser fileChooser = new JFileChooser();
+        fileChooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
+        if (fileChooser.showDialog(null, "OK") != JFileChooser.APPROVE_OPTION)
+            return null;
+        return fileChooser.getSelectedFile();
+    }
+
+    private static boolean isImage(Path p) {
+        try {
+            String content = Files.probeContentType(p);
+            if (content == null) return false;
+            return content.split("/")[0].equals("image");
+        } catch (IOException e) {
+            e.printStackTrace();
+            return false;
+        }
+    }
+}