Captcha Image Creation in struts - Java code

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.font.FontRenderContext;
import java.awt.font.TextLayout;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Random;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class Captcha extends Action {

private static final long serialVersionUID = 1L;

private Random generator = new Random();
private final static String SIMPLE_CAPCHA_SESSION_KEY = "SIMPLE_CAPCHA_SESSION_KEY";


private static char[] captchars =
new char[] {
'A',
'B',
'C',
'D',
'E',
'2',
'3',
'4',
'5',
'6',
'7',
'8',
'G',
'F',
'H',
'Q',
'R',
'Y',
'N',
'M',
'P',
'U',
'V',
'Z',
'W',
'X'
};

public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest req,
HttpServletResponse resp) throws IOException, ServletException{

//System.out.println("Inside Captcha");

//ActionForward actionForward;
//HttpSession session = request.getSession();

//=========================================================================================
int ImageWidth = 200;
int ImageHeight = 70;

int car = captchars.length - 1;

String test = "";
for (int i = 0; i < 6; i++) {
test += captchars[generator.nextInt(car) + 1];
}
// this key can be read from any controller to check whether user
// is a computer or human..

req.getSession().setAttribute(Captcha.SIMPLE_CAPCHA_SESSION_KEY, test);

req.setAttribute("test", test);

//System.out.println("++++++++++++++++++++++++++++++++++++++++++= " + test);
//System.out.println("++++++++++++++++++++++++++++++++++++++++++= " + req.getAttribute("test"));
//System.out.println("++++++++++++++++++++++++++++++++++++++++++= " + req.getSession().getAttribute(Captcha.SIMPLE_CAPCHA_SESSION_KEY));
BufferedImage bi =
new BufferedImage(
ImageWidth + 10,
ImageHeight,
BufferedImage.TYPE_BYTE_INDEXED);

Graphics2D graphics = bi.createGraphics();
graphics.setBackground(Color.white);
graphics.setColor(Color.white);

graphics.fillRect(0, 0, bi.getWidth(), bi.getHeight());

//graphics.drawLine( 0, generator.nextInt(ImageHeight)+1, ImageWidth, generator.nextInt(ImageHeight)+1);

graphics.setColor(Color.black);
//AttributedString attstr = new AttributedString(test);

//graphics.drawString(attstr.getIterator(), 0, 50);

//Font font = new Font()

TextLayout textTl =
new TextLayout(
test,
new Font("Courier", Font.BOLD, 40),
new FontRenderContext(null, true, false));
//AffineTransform textAt = graphics.getTransform();

textTl.draw(graphics, 50, 50);
int w = bi.getWidth();
int h = bi.getHeight();
shear(graphics, w, h, Color.black);
this.drawThickLine(
graphics,
50,
generator.nextInt(ImageHeight) + 1,
ImageWidth,
generator.nextInt(ImageHeight) + 1,
4,
Color.getColor("#FFFFFF"));
resp.setContentType("image/jpg");

try {
JPEGImageEncoder encoder =
JPEGCodec.createJPEGEncoder(resp.getOutputStream());
//System.out.println("------------->"+ encoder);
encoder.encode(bi);
} catch (IllegalArgumentException e) {
resp.sendError(HttpServletResponse.SC_NOT_FOUND);
e.printStackTrace();
return null;
}
//=========================================================================================



return null;
}

private void shear(Graphics g, int w1, int h1, Color color) {

shearX(g, w1, h1, color);
shearY(g, w1, h1, color);
}

public void shearX(Graphics g, int w1, int h1, Color color) {

int period = generator.nextInt(10) + 5;

boolean borderGap = true;
int frames = 15;
int phase = generator.nextInt(5) + 2;

for (int i = 0; i < h1; i++) {
double d =
(double) (period >> 1)
* Math.sin(
(double) i / (double) period
+ (6.2831853071795862D * (double) phase)
/ (double) frames);
g.copyArea(0, i, w1, 1, (int) d, 0);
if (borderGap) {
g.setColor(color);
g.drawLine((int) d, i, 0, i);
g.drawLine((int) d + w1, i, w1, i);
}
}

}

public void shearY(Graphics g, int w1, int h1, Color color) {

int period = generator.nextInt(30) + 10; // 50;

boolean borderGap = true;
int frames = 15;
int phase = 7;
for (int i = 0; i < w1; i++) {
double d =
(double) (period >> 1)
* Math.sin(
(double) i / (double) period
+ (6.2831853071795862D * (double) phase)
/ (double) frames);
g.copyArea(i, 0, 1, h1, 0, (int) d);
if (borderGap) {
g.setColor(color);
g.drawLine(i, (int) d, i, 0);
g.drawLine(i, (int) d + h1, i, h1);
}

}

}

private void drawThickLine(
Graphics g,
int x1,
int y1,
int x2,
int y2,
int thickness,
Color c) {


// The thick line is in fact a filled polygon
g.setColor(c);
int dX = x2 - x1;
int dY = y2 - y1;
// line length
double lineLength = Math.sqrt(dX * dX + dY * dY);

double scale = (double) (thickness) / (2 * lineLength);

// The x and y increments from an endpoint needed to create a rectangle...
double ddx = -scale * (double) dY;
double ddy = scale * (double) dX;
ddx += (ddx > 0) ? 0.5 : -0.5;
ddy += (ddy > 0) ? 0.5 : -0.5;
int dx = (int) ddx;
int dy = (int) ddy;

// Now we can compute the corner points...
int xPoints[] = new int[4];
int yPoints[] = new int[4];

xPoints[0] = x1 + dx;
yPoints[0] = y1 + dy;
xPoints[1] = x1 - dx;
yPoints[1] = y1 - dy;
xPoints[2] = x2 - dx;
yPoints[2] = y2 - dy;
xPoints[3] = x2 + dx;
yPoints[3] = y2 + dy;

g.fillPolygon(xPoints, yPoints, 4);
}


}