private String readLine(BufferedReader commandReader) {
		String commandLine = null;
		do
			try {
				commandLine = commandReader.readLine();
				this.log.info("Read one command line" + commandLine);
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
				this.log.info("Read one command line: fail IOException");
				commandLine = null;
			}
		while (commandLine == null);
		return commandLine;
	}