tic-tac-toe/src/Main.java

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		
		PlayField field = new PlayField();
		int nextPos;
		boolean won;
		Scanner myScanner = new Scanner(System.in);
		
		do {
			
			System.out.println("Where do you want to set your 'x'? (1-9)");
			
			do {
				//Check input
				if(!myScanner.hasNextInt()) {
					System.out.println("Invalid input. Try again.");
					myScanner.nextLine();
					continue;
				}
				nextPos = myScanner.nextInt();
				if(nextPos < 1 || nextPos > 9) {
					System.out.println("Invalid int. 1 to 9 expected.");
					myScanner.nextLine();
					continue;
				}
				if(field.getPos(nextPos) != 0) {
					System.out.println("Position not free.");
					myScanner.nextLine();
					continue;
				}
				
				//Player's turn
				won = field.updatePos(nextPos, 1);
				if(won) {
					printWinner(1);
					if(!askPlayAgain(myScanner)) {
						myScanner.close();
						System.exit(0);
					}
					field.resetField();
					break;
					
				}
				if(field.isDraw()) {
					System.out.println("Draw.");
					if(!askPlayAgain(myScanner)) {
						System.out.println("Game closed.");
						myScanner.close();
						System.exit(0);
					}
					field.resetField();
					break;
				}
				
				//Opponent's turn
				System.out.println("Opponents turn:");
				won = field.oppMove();
				if(won) {
					printWinner(2);
					if(!askPlayAgain(myScanner)) {
						System.out.println("Game closed.");
						myScanner.close();
						System.exit(0);
					}
					field.resetField();
					break;
					
				}
				if(field.isDraw()) {
					System.out.println("Draw.");
					if(!askPlayAgain(myScanner)) {
						System.out.println("Game closed.");
						myScanner.close();
						System.exit(0);
					}
					field.resetField();
					break;
				}
				
				break;
				
			} while(true);

		} while (true);
		
	}
	
	public static void printWinner(int player) {
		if(player == 1) {
			System.out.println("Player 'x' has won.");
		} else {
			System.out.println("Player 'o' has won.");
		}
	}
	
	private static boolean askPlayAgain(Scanner in) {
		String again;
		System.out.println("New game? Y/N");
		do {
			again = in.next();
			if(again.equals("Y")) {
				return true;
			} else if(again.equals("N")) {
				return false;
			} else {
				System.out.println("Invalid input. Try again.");
			}
		} while(true);
	}	
	
}