add native open, save dlg in macOS

app/src/main/groovy/org/jd/gui/util/io/FileUtils.groovy

@@ -0,0 +1,20 @@
+package org.jd.gui.util.io
+
+/**
+ * Created by jianhua.fengjh on 27/11/2015.
+ */
+class FileUtils {
+
+    static String ensureTrailingSlash(final String path) {
+        if ((path == null) || "".equals(path)) {
+            return "";
+        }
+
+        StringBuilder buf = new StringBuilder(path);
+        while (buf.charAt(buf.length() - 1) == File.separatorChar) {
+            buf.deleteCharAt(buf.length() - 1);
+        }
+
+        return buf.append(File.separatorChar).toString();
+    }
+}

app/src/main/groovy/org/jd/gui/util/sys/SystemUtils.groovy

@@ -0,0 +1,20 @@
+package org.jd.gui.util.sys
+
+/**
+ * Created by jianhua.fengjh on 27/11/2015.
+ */
+final class SystemUtils {
+
+    static boolean isLinux() {
+        return System.getProperty("os.name").startsWith("Linux");
+    }
+
+    static boolean isMacOS() {
+        return System.getProperty("os.name").startsWith("Mac");
+    }
+
+    static boolean isWindows() {
+        return System.getProperty("os.name").startsWith("Windows");
+    }
+
+}

app/src/main/groovy/org/jd/gui/view/MainView.groovy

@@ -23,6 +23,7 @@ import org.jd.gui.api.feature.UriOpenable
 import org.jd.gui.model.configuration.Configuration
 import org.jd.gui.model.history.History
 import org.jd.gui.spi.FileLoader
+import org.jd.gui.view.component.FileChooser
 
 import javax.swing.Icon
 import javax.swing.JComponent
@@ -199,7 +200,7 @@ class MainView implements UriOpenable, PreferencesChangeListener {
     }
 
 	JFileChooser createOpenFileChooser() {
-		JFileChooser chooser = new JFileChooser() {
+		FileChooser chooser = new FileChooser() {
             void addFileFilters(Map<String, FileLoader> loaders) {
                 removeChoosableFileFilter(getFileFilter())
 
@@ -223,7 +224,7 @@ class MainView implements UriOpenable, PreferencesChangeListener {
 	}
 
     JFileChooser createSaveFileChooser() {
-        JFileChooser chooser = new JFileChooser() {
+        FileChooser chooser = new FileChooser() {
             void show(Closure okClosure) {
                 if (showSaveDialog(swing.mainFrame) == JFileChooser.APPROVE_OPTION) {
                     if (selectedFile.exists()) {

app/src/main/groovy/org/jd/gui/view/component/FileChooser.groovy

@@ -0,0 +1,87 @@
+package org.jd.gui.view.component
+
+import org.jd.gui.util.io.FileUtils
+import org.jd.gui.util.sys.SystemUtils
+
+import javax.swing.*
+import java.awt.*
+
+/**
+ * Created by jianhua.fengjh on 27/11/2015.
+ */
+class FileChooser extends JFileChooser {
+
+    int showOpenDialog(Component parent) {
+        if (!SystemUtils.isMacOS()) {
+            return super.showOpenDialog(parent);
+        } else {
+            setDialogType(JFileChooser.OPEN_DIALOG);
+            return showNativeFileDialog(this);
+        }
+    }
+
+    int showSaveDialog(Component parent) {
+
+        if (!SystemUtils.isMacOS()) {
+            return super.showSaveDialog(parent);
+        } else {
+            setDialogType(JFileChooser.SAVE_DIALOG);
+            return showNativeFileDialog(this);
+        }
+    }
+
+    private static int showNativeFileDialog(final JFileChooser chooser) {
+        if (chooser != null) {
+
+            FileDialog fileDialog = new FileDialog((Frame) chooser.getParent());
+            fileDialog.setDirectory(chooser.getCurrentDirectory().getPath());
+            File file = chooser.getSelectedFile();
+
+            if (chooser.getDialogType() == JFileChooser.SAVE_DIALOG) {
+                fileDialog.setFile(file != null ? file.getName() : ""); //save only need name
+            } else {
+                fileDialog.setFile(file != null ? file.getPath() : "");
+            }
+
+            fileDialog.setFilenameFilter(new FilenameFilter() {
+
+                boolean accept(File dir, String name) {
+                    String path = dir.getPath();
+                    String pathSeparator = File.pathSeparator;
+                    return chooser.getFileFilter().accept(new File(0 + path.length() + pathSeparator.length() + name.length() + path + pathSeparator + name));
+                }
+
+            });
+
+            if (chooser.getDialogType() == JFileChooser.SAVE_DIALOG) {
+                fileDialog.setMode(FileDialog.SAVE);
+            } else {
+                fileDialog.setMode(FileDialog.LOAD);
+            }
+
+            if (chooser.getFileSelectionMode() == JFileChooser.DIRECTORIES_ONLY) {
+                System.setProperty("apple.awt.fileDialogForDirectories", "true");
+            } else {
+                System.setProperty("apple.awt.fileDialogForDirectories", "false");
+            }
+
+            fileDialog.setVisible(true);
+
+            //reset fileDialogForDirectories property
+            System.setProperty("apple.awt.fileDialogForDirectories", "false");
+            if (fileDialog.getFile() == null) {
+                return JFileChooser.CANCEL_OPTION;
+            }
+
+            String dir = fileDialog.getDirectory();
+            String trailingSlash = FileUtils.ensureTrailingSlash(dir);
+            String strFile = fileDialog.getFile();
+            chooser.setSelectedFile(new File(strFile.length() != 0 ? trailingSlash.concat(strFile) : trailingSlash));
+
+            return JFileChooser.APPROVE_OPTION;
+        }
+
+        return JFileChooser.ERROR_OPTION;
+    }
+
+}