Cell.java

package sudoku;
import java.awt.Color;
import java.awt.Font;
import javax.swing.JTextField;
//import java.text.NumberFormat;
//import javax.swing.JFormattedTextField;
/**
 * The Cell class model the cells of the Sudoku puzzle, by customizing (subclass)
 * the javax.swing.JTextField to include row/column, puzzle number and status.
 */
public class Cell extends JTextField{
    private static final long serialVersionUID = 1L;  // to prevent serial warning

    public static final Color BG_GIVEN = new Color(240, 240, 240); // RGB
    public static final Color FG_GIVEN = Color.BLACK;
    public static final Color FG_NOT_GIVEN = Color.GRAY;
    public static final Color BG_TO_GUESS  = Color.YELLOW;
    public static final Color BG_CORRECT_GUESS = new Color(0, 216, 0);
    public static final Color BG_WRONG_GUESS  = new Color(216, 0, 0);
    public static final Font FONT_NUMBERS = new Font("OCR A Extended", Font.PLAIN, 30);


    int row, col;
    int number;
    CellStatus status;

    public Cell(int row, int col) {
        super();
        this.row = row;
        this.col = col;
        // Inherited from JTextField: Beautify all the cells once for all
        super.setHorizontalAlignment(JTextField.CENTER);
        super.setFont(FONT_NUMBERS);
    }

    public JTextField getTextField() {
        return this;
    }

    public void setNumber(int number) {
        this.number = number;
    }

    public void newGame(int number, boolean isGiven) {
        this.number = number;
        if (isGiven) {
            status = CellStatus.GIVEN;
        } else {
            status = CellStatus.TO_GUESS;
        }
        paint();    // paint itself
    }


    public void paint() {
        if (status == CellStatus.GIVEN) {
            // Inherited from JTextField: Set display properties
            super.setText(number + "");
            super.setEditable(false);
            super.setBackground(BG_GIVEN);
            super.setForeground(FG_GIVEN);
        } else if (status == CellStatus.TO_GUESS) {
            // Inherited from JTextField: Set display properties
            super.setText("");
            super.setEditable(true);
            super.setBackground(BG_TO_GUESS);
            super.setForeground(FG_NOT_GIVEN);
        } else if (status == CellStatus.CORRECT_GUESS) {  // from TO_GUESS
            super.setBackground(BG_CORRECT_GUESS);
        } else if (status == CellStatus.WRONG_GUESS) {    // from TO_GUESS
            super.setBackground(BG_WRONG_GUESS);
        }
    }

}