private int getStatusCode(@Nullable final byte[] response, final int request)
			throws UnknownResponseException {
		if (response == null || response.length != 3 || response[0] != OP_CODE_RESPONSE_CODE_KEY ||
				response[1] != request || response[2] < 1 || response[2] > 6)
			throw new UnknownResponseException("Invalid response received", response, OP_CODE_RESPONSE_CODE_KEY, request);
		return response[2];
	}
private int getStatusCode ( @ Nullable final byte [ ] response , final int request ) throws UnknownResponseException { if ( response == null || response . length != 3 || response [ 0 ] != OP_CODE_RESPONSE_CODE_KEY || response [ 1 ] != request || response [ 2 ] < 1 || response [ 2 ] > 6 ) throw new UnknownResponseException ( "Invalid response received" , response , OP_CODE_RESPONSE_CODE_KEY , request ) ; return response [ 2 ] ; }
Checks whether the response received is valid and returns the status code.

@param response the response received from the DFU device.
@param request  the expected Op Code.
@return The status code.
@throws UnknownResponseException if response was not valid.