GameObject.java

import java.awt.*;
import javax.swing.JComponent;

/**
 * An abstract class for an object which can be added to an instance of
 * <code>Game</code><br>
 * <br>
 * The <code>act</code> method can be implemented to provide a behavior for
 * the object, and will be called every millisecond automatically by a <code>
 * Game</code> it has been added to.<br>
 * @see Game#add
 */
public abstract class GameObject extends JComponent {
    Color c = Color.red;

    /**
     * Sets the pixel width and height of the object
     *
     * @param width  a width in pixels
     * @param height a height in pixels
     */
    public void setSize(int width, int height) {
        super.setSize(width, height);
    }

    /**
     * Gets the x component of the coordinate of the upper left corner of
     * this object
     *
     * The coordinate is relative to the playing field, with <code>0</code>
     * being the far left of the field, and positive values moving toward the right
     * of the field
     */
    public int getX() {
        return getLocation().x;
    }

    /**
     * Gets the y component of the coordinate of the upper left corner of
     * this object
     *
     * The coordinate is relative to the playing field, with <code>0</code>
     * being the top of the field, and positive values moving toward the
     * bottom of the field
     */
    public int getY() {
        return getLocation().y;
    }

    /**
     * Sets the x (horizontal) position of this object
     *
     * Setting the x position will not affect the y position
     *
     * @param x  the x position of the upper left corner of this object
     */
    public void setX(int x) {
        super.setLocation(x, getLocation().y);
    }

    /**
     * Sets the y (vertical) position of this object
     *
     * Setting the y position will not affect the x position
     *
     * @param y  the y position of the upper left corner of this object
     */
    public void setY(int y) {
        super.setLocation(getLocation().x, y);
    }

    /**
     * Sets the color of this object
     *
     * @param c  the color of this object
     * @see   java.awt.Color
     */
    public void setColor(Color c) {
        this.c = c;
    }

    /**
     * Paints the object on the screen. This is called automatically.
     *
     * Child classes should not implement or override this method.
     */
    public void paint(Graphics g) {
        Rectangle r = getBounds();
        g.setColor(c);
        g.fillRect(0, 0, (int)r.getWidth(), (int)r.getHeight());
    }

    /**
     * Returns <code>true</code> if this object collides with another
     * <code>GameObject</code>
     *
     * @param o  the <code>GameObject</code> to test for collision
     * @return  <code>true</code> if collision occurs
     */
    public boolean collides(GameObject o) {
        return getBounds().intersects(o.getBounds());
    }

    /**
     * This method should be implemented to provide a <i>behavior</i>
     * for this object.
     *
     * The <code>Game</code> will automatically call this method every
     * millisecond. It can be implemented to provide basic behavior for
     * an object, such as movement.
     */
    public abstract void act();
}