CS1 Standard Demo Page

/*
 * Program to paint a rectangle,centered in the canvas, made up of randomly
 * colored, black framed squares.
 */
package npw;

import java.awt.Color;
import java.util.Random;
import javax.swing.JOptionPane;
import javax.swing.SwingUtilities;
import painter.SPainter;
import shapes.SSquare;
import java.util.Scanner;

/**
 *
 * @author ecuevas
 */
public class Number2 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable(){
            public void run() {
                new Number2();
        }  
    });
}

public Number2(){
    paintTheImage();
}
 
// The Solution To The Graphical Problem

private void paintTheImage(){
    // GRAB THE INPUT INFORMATION
    int nrOfRows = getNumber("rows");
    int nrOfColumns = getNumber("columns");
    int sizeOfSquare = getNumber("square side length");
    // ESTABLISH THE PAINTER
    int height = nrOfRows * sizeOfSquare;
    int width = nrOfColumns * sizeOfSquare;
    SPainter miro = new SPainter("Number 1",width+50,height+50);
    miro.setBrushWidth(4);
    SSquare square = new SSquare(sizeOfSquare);
    // PAINT THE RECTANGLES
    paintRectangle(miro,square,nrOfRows,nrOfColumns);
}
    private static int getNumber(String prompt) {
        String nss = JOptionPane.showInputDialog(null,prompt+"?");
        Scanner scanner = new Scanner(nss);
        return scanner.nextInt();  
    }

    private static void paintRectangle(SPainter miro, SSquare square, int nrOfRows,
    int nrOfColumns) {
        // POSITION THE PAINTER TO PAINT THE RECTANGLE OF SQUARES
        miro.mlt(((nrOfColumns-1)/2.0)*square.side());
        miro.mbk(((nrOfRows-1)/2)*square.side());
        // PAINT THE RECTANGLE OF SQUARES
        int i = 1;
        while (i <= nrOfRows){
            paintOneRow(miro,nrOfColumns,square);
            miro.mfd(square.side());
            i = i + 1;
        }
        // MAKE THE METHOD INVARIANT WITH RESPECT TO PAINTER POSITION
        miro.mrt(((nrOfColumns-1)/2.0)*square.side());
        miro.mfd(((nrOfRows-1)/2.0)*square.side());
    }

    private static void paintOneRow(SPainter miro, int nrOfColumns, SSquare square) {
        int i = 1;
        while (i <= nrOfColumns ){
            paintOneSquare(miro,square);
            miro.mrt(square.side());
            i = i + 1;
        }
        miro.mlt(nrOfColumns*square.side());
    }

    private static void paintOneSquare(SPainter miro, SSquare square) {
        square.s2();
        miro.setColor(randomColor());
        miro.paint(square);
        miro.setColor(Color.BLACK);
        miro.draw(square);
        square.x2();
    }

    private static Color randomColor() {
        Random rgen = new Random();
        int r = rgen.nextInt(256);
        int g = rgen.nextInt(256);
        int b = rgen.nextInt(256);
        return new Color(r,b,g);
    }
}