public class Game {
    private static Character character;
    public void getInput() {
        character = new Character();
                Vector2Float char_position = new Vector2Float(character.getSX(), character.getSY());
        Vector2Float motion = new Vector2Float();

        if (Keyboard.isKeyDown(Keyboard.KEY_W)) {
            motion.add(new Vector2Float(0,1);
        }
        if (Keyboard.isKeyDown(Keyboard.KEY_S)){
            motion.add(new Vector2Float(0,-1);
        }
        if (Keyboard.isKeyDown(Keyboard.KEY_A)){
            motion.add(new Vector2Float(-1,0);
        }
        if (Keyboard.isKeyDown(Keyboard.KEY_D)){
            motion.add(new Vector2Float(1,0);
        }

        coll = new Collision(char_position, motion, this);
        if (!coll.getResult())
        {
            character.setPosition(char_position.add(motion));
        }
    }
}

public class Vector2Float
{
    public float X, Y;
    public Vector2Float()
    {
      this.X = 0;
      this.Y = 0;
    }
    public Vector2Float(float x, float y)
    {
      this.X = x;
      this.Y = y;
    }
    public void setValues(float x, float y)
    {
      this.X = x;
      this.Y = y;
    }
    public float add(Vector2Float other)
    {
      return new Vector2Float(this.X + other.X, this.Y + other.Y);
    }
    public float getX()
    {
      return X;
    }
    public float getY()
    {
      return Y;
    }
}

public class Collision {
    private Character character;
    private Game game;
    private static Game default_game = new Game(); //may want to fix that
    public static float BORDER_TOP = 600;
    public static float BORDER_BOTTOM = 0;
    public static float BORDER_LEFT = 0;
    public static float BORDER_RIGHT = 800;
    /**
     * False if movement should be denied.
     */
    protected boolean result;
    /**
     * Change the boundaries of the arena.
     * @param topy - Y-ceiling.
     * @param boty - Y-floor.
     * @param rigx - X-ceiling.
     * @param lefx - X-floor.
     */
    public static void changeBounds(float topy, float boty, float lefx, float rigx)
    {
    BORDER_TOP = topy;
    BORDER_BOTTOM = boty;
    BORDER_LEFT = lefx;
    BORDER_RIGHT = rigx;
    }

    public Collision(Character player)
    {
        character = player;
        game = default_game;
        update();
    }
    public Collision(Vector2Float pos, Vector2Float motion, Game g)
    {
        game = g;
        update(pos,motion);
    }
    public boolean update()
    {
        result = true;
        pos_x = character.getSX();
        pos_y = character.getSY();
        if (pos_x < BORDER_LEFT) result = false;
        if (pos_x > BORDER_RIGHT) result = false;
        if (pos_y < BORDER_BOTTOM) result = false;
        if (pos_y > BORDER_TOP) result = false;

        if (!result) {
            return result;
        }
        /*
        CollisionBoundary[] objects = game.getAllCollisionObjects();
        for (CollisionBoundary bound : objects)
        {
            // ...
        }
        */
        return result;
    }
    public boolean getResult()
    {
        return result;
    }
}