adjust selected File to FileFilter in a JFileChooser

Question

I\'m writing a diagram editor in java. This app has the option to export to various standard image formats such as .jpg, .png etc. When the user clicks File->Export, you get

Answer 1

How about this:

class MyFileChooser extends JFileChooser {
   public void setFileFilter(FileFilter filter) {

    super.setFileFilter(filter);

    FileChooserUI ui = getUI();

    if( ui instanceof BasicFileChooserUI ) {
     BasicFileChooserUI bui = (BasicFileChooserUI) ui;

     String file = bui.getFileName();

     if( file != null ) {
      String newFileName = ... change extension 
      bui.setFileName( newFileName );
     }
    }
   }
  }