public void write(String str,int off,int len) throws IOException {
  if (_output == null)   throw new IOException("Writer closed");
  _output.append(str,off,off + len);
}

public void write ( String str , int off , int len ) throws IOException { if ( _output == null ) throw new IOException ( "Writer closed" ) ; _output . append ( str , off , off + len ) ; }
writes a portion of a string .
