How would i make an object and rotate it?

Question

ok, i'm trying to get java to make a graphics object, and then create an array of said objects (basically just a bunch of rectangles organized into rows/columns) with the end goal being that i be able to put this collection of rectangles into a JPanel and then move it around and rotate it without changing its dimensions (so each rectangle in the collection retains the same height and width but with a different placement/orientation angle )
My java textbook (yes, college student) doesn't cover the Graphics2D stuff which SEEMS to be what i would use... but beyond that I'm finding the resources on the topic to be uniformly opaque. i think i just need some starting point to extrapolate from. could anyone reply me a crash course in the above...?

Answer 1

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Blocks extends JPanel {
    Block[][] blocks;
    int dx = 2;
    int dy = 2;
    public Blocks() {
        registerKeys();
        setFocusable(true);
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        if(blocks == null) initBlocks();
        g2.setPaint(Color.red);
        for(int j = 0; j < blocks.length; j++)
            for(int k = 0; k < blocks[j].length; k++)
                blocks[j][k].draw(g2);
    private void initBlocks() {
        int rows = 6;
        int cols = 3;
        Dimension d = new Dimension(200, 200);
        BlockMaker blockMaker = new BlockMaker(rows, cols, d);
        blocks = blockMaker.getBlocks();
    private void registerKeys() {
        getInputMap().put(KeyStroke.getKeyStroke("UP"), "UP");
        getActionMap().put("UP", up);
        getInputMap().put(KeyStroke.getKeyStroke("LEFT"), "LEFT");
        getActionMap().put("LEFT", left);
        getInputMap().put(KeyStroke.getKeyStroke("DOWN"), "DOWN");
        getActionMap().put("DOWN", down);
        getInputMap().put(KeyStroke.getKeyStroke("RIGHT"), "RIGHT");
        getActionMap().put("RIGHT", right);
    private void step(int x, int y) {
        for(int j = 0; j < blocks.length; j++)
            for(int k = 0; k < blocks[j].length; k++)
                blocks[j][k].move(x, y);
        repaint();
    private Action up = new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            step(0, -dy);
    private Action left = new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            step(-dx, 0);
    private Action down = new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            step(0, dy);
    private Action right = new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            step(dx, 0);
    public static void main(String[] args) {
        Blocks blocks = new Blocks();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(blocks);
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
class BlockMaker {
    Block[][] blocks;
    int PAD = 20;
    public BlockMaker(int rows, int cols, Dimension size) {
        int w = (size.width  - (cols+1)*PAD)/cols;
        int h = (size.height - (rows+1)*PAD)/rows;
        blocks = new Block[rows][cols];
        for(int j = 0; j < rows; j++) {
            int y = PAD + j*(h + PAD);
            for(int k = 0; k < cols; k++) {
                int x = PAD + k*(w + PAD);
                blocks[j][k] = new Block(x, y, w, h);
    public Block[][] getBlocks() {
        return blocks;
class Block {
    int x;
    int y;
    int w;
    int h;
    public Block(int x, int y, int w, int h) {
        this.x = x;
        this.y = y;
        this.w = w;
        this.h = h;
    protected void draw(Graphics2D g2) {
        g2.drawRect(x, y, w, h);
    protected void move(int dx, int dy) {
        x += dx;
        y += dy;
}