private static COMMAND_TYPE determineCommand(String command) {
		if (command.equals("add")) {
			return COMMAND_TYPE.ADD_EVENT;
		} else if (command.equals("delete")) {
			return COMMAND_TYPE.DELETE_EVENT;
		} else if (command.equals("display")) {
			return COMMAND_TYPE.DISPLAY_EVENTS;
		} else if (command.equals("clear")) {
			return COMMAND_TYPE.CLEAR_EVENTS;
		} else if (command.equals("sort")) {
			return COMMAND_TYPE.SORT_EVENTS;
		} else if (command.equals("search")) {
			return COMMAND_TYPE.SEARCH_EVENT;
		} else if (command.equals("exit")) {
			return COMMAND_TYPE.EXIT;
		} else {
			return COMMAND_TYPE.INVALID;
		}
	}