Use a more factory like pattern to crate fileDialogs

Avoids unnecessary constructor overloads

src/main/java/net/sf/jabref/gui/NewFileDialogs.java

@@ -9,6 +9,8 @@
 
 import javax.swing.JFileChooser;
 import javax.swing.JFrame;
+import javax.swing.filechooser.FileFilter;
+import javax.swing.filechooser.FileNameExtensionFilter;
 
 import net.sf.jabref.Globals;
 import net.sf.jabref.JabRefPreferences;
@@ -20,6 +22,53 @@
  */
 public class NewFileDialogs {
 
+    private final JFileChooser fileChooser = new JFileChooser();
+    private final JFrame parent;
+    private final String directory;
+    private FileFilter extFilter;
+
+
+    public NewFileDialogs(JFrame owner) {
+        this(owner, getWorkingDir());
+    }
+
+    public NewFileDialogs(JFrame owner, String dir) {
+        this.parent = owner;
+        this.directory = dir;
+        fileChooser.setCurrentDirectory(Paths.get(dir).toFile());
+
+    }
+
+    public NewFileDialogs SaveFileDialog() {
+        fileChooser.setDialogType(JFileChooser.SAVE_DIALOG);
+        return this;
+    }
+
+    public NewFileDialogs OpenFileDialog() {
+        fileChooser.setDialogType(JFileChooser.OPEN_DIALOG);
+        return this;
+    }
+
+    public NewFileDialogs withExtension(String... ext) {
+        extFilter = new FileNameExtensionFilter("", ext);
+        fileChooser.setFileFilter(extFilter);
+        return this;
+    }
+
+    public NewFileDialogs updateWorkingDirectory() {
+        updateWorkingDirectorySetting(this.directory);
+        return this;
+    }
+
+    public List<String> getMultipleFileNames() {
+        return Collections.emptyList();
+
+    }
+
+    public String getFileName() {
+        return "";
+    }
+
     public static List<String> getMultipleFiles(JFrame owner, String extension, boolean workingDir,
             boolean updateWorkingDirSetting) {
 
@@ -56,6 +105,10 @@ public static List<String> getMultipleFiles(JFrame owner, Path directory, String
 
     }
 
+    private static String getWorkingDir() {
+        return Globals.prefs.get(JabRefPreferences.WORKING_DIRECTORY);
+    }
+
     private static void updateWorkingDirectorySetting(String dir) {
         Globals.prefs.put(JabRefPreferences.WORKING_DIRECTORY, dir);