code: protected boolean fileExistsAndIsReadable(String filename) {
  
      File f = new File(filename);
      return f.exists() && f.isFile() && f.canRead();
    }
docs: Convenience method to check if a file exists and is readable
  
  @param filename
  the file to be checked
  @return <code>true</code> if the file exists and is readable,
  <code>false</code> otherwise