public static String[] validateCommand(String line){
		String[] data = line.split(" ");
		for (int i = 0; i < data.length; i++){	
			if (!data[i].matches("[A-Za-z0-9]+"))
				return (new String[]{});
		}
		
		if (data.length < 3 || data.length > 4 || (!data[0].equals("read") && !data[0].equals("write")) || (data[0].equals("write") && data.length < 4))
			return (new String[]{});
	
		return data;
	}