rotatePdf input.pdf output.pdf 180

import com.lowagie.text.DocumentException;
import com.lowagie.text.pdf.PdfNumber;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfName;
import com.lowagie.text.pdf.PdfStamper;
import java.io.FileOutputStream;
import java.io.IOException;

public class RotatePages
{
    public static void main(String[] args)
    {
        String fileName = "";
        String outFileName = "";
        int degrees = 0;
        String usage = "usage: RotatePages <input> <output> <degrees>";

        if (args.length > 2)
        {
            fileName = args[0];
            outFileName = args[1];
            try
            {
                degrees = Integer.parseInt(args[2]);
                if (degrees != 90 && degrees != 180)
                {
                    System.out.println("Entered: " + degrees);
                    throw new NumberFormatException();
                }
            }
            catch (NumberFormatException e)
            {
                System.out.println(usage);
                System.out.println("Please specify either 90 or 180 degrees.");
                return;
            }
        }
        else
        {
            System.out.println(usage);
            return;
        }
        try
        {
            System.out.println("Rotating all pages in " + fileName + " by "
                + degrees + " degrees.");

            PdfReader reader = new PdfReader(fileName);

            for (int p = 1; p <= reader.getNumberOfPages(); ++p)
            {
                reader.getPageN(p).put(PdfName.ROTATE, new PdfNumber(degrees));
            }

            PdfStamper stp = new PdfStamper(reader, new FileOutputStream(
                outFileName));
            stp.close();
            System.out.println("Writing " + outFileName + " ...");
        }
        catch (DocumentException e)
        {
            e.printStackTrace();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
}