Question

I am working on a Server Client program in Java, using Sockets.

I ask the user to input a series of integers, add them in an ArrayList and send them over to the server as an Object using ObjectOutputStream. The Server then receives the object.

I parse the object as an ArrayList and then I use a method to calculate what is the maximum number of the integers and return it as a string to the client.

I am using BufferedReader for the user input

In a sense what I need is a logic on how to:

To check for the users input, if it is not “Ok” or press Enter

The user should be able to add numbers separated by a space.

If then he presses Enter then should exit the loop and the numbers add at the array

I have so far:

 BufferedReader integers = new BufferedReader(new InputStreamReader(System.in));
                        //  send int 1, for the Max number option
                        pw.println(option);
                        System.out.println(br.readLine());
                        String x = integers.readLine();
                        if(integers!=null){

                            readInt(integers);

                    }


                        objectOut = new ObjectOutputStream(client.getOutputStream());
                        objectOut.writeObject(maxNum);
                        objectOut.flush();
                        System.out.println(br.readLine());
                        objectOut.close();
                        break;

The readIn method:

public static int readInt(BufferedReader stdIn) {
        while (true) {
            try {
                String line = stdIn.readLine();
                int value = Integer.parseInt(line);
                return value;
            } catch (java.lang.NumberFormatException e) {
                ;
            } catch (IOException e) {
                ;
            }
        }
    }

Answer 1

You can better handle this with Scanner. BufferedReader is quite old and deprecated.

List<Integer> seriesOfInt = new ArrayList<>();

while (scanner.hasNextInt()) {
    seriesOfInt.add(scanner.nextInt());
}

Or, if user is entering all those numbers in one line with some delimiter between them, say a whitespace (), you can split the input and store in ArrayList..

if (scanner.hasNext()) {
    List<String> seriesOfIntString = Arrays.asList(scanner.next().split(" "));
}