code: public QrCodeEncoder addAlphanumeric(String alphaNumeric) {
  		byte values[] = alphanumericToValues(alphaNumeric);
  
  		MessageSegment segment = new MessageSegment();
  		segment.message = alphaNumeric;
  		segment.data = values;
  		segment.length = values.length;
  		segment.mode = QrCode.Mode.ALPHANUMERIC;
  
  		segment.encodedSizeBits += 4;
  		segment.encodedSizeBits += 11*(segment.length/2);
  		if( segment.length%2 == 1 ) {
  			segment.encodedSizeBits += 6;
  		}
  
  		segments.add(segment);
  
  		return this;
  	}
docs: Creates a QR-Code which encodes data in the alphanumeric format
  
  @param alphaNumeric String containing only alphanumeric values.
  @return The QR-Code