Groovy example source code file (mandelbrot.java)

This example Groovy source code file (mandelbrot.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

buffer_size, buffer_size, ci, cr, io, ioexception, mandelbrot, p4\n, zi, zi, zin, zin, zr, zr, zrn

The Groovy mandelbrot.java source code

/* The Computer Language Benchmarks Game
   http://shootout.alioth.debian.org/
   contributed by Stefan Krause
   slightly modified by Chad Whipkey
*/

import java.io.IOException;
import java.io.PrintStream;

class mandelbrot {

   public static void main(String[] args) throws Exception {
       new Mandelbrot(Integer.parseInt(args[0])).compute();
   }

   public static class Mandelbrot {
       private static final int BUFFER_SIZE = 8192;

       public Mandelbrot(int size) {
         this.size = size;
         fac = 2.0 / size;
         out = System.out;
         shift = size % 8 == 0 ? 0 : (8- size % 8);
      }
      final int size;
      final PrintStream out;
      final byte [] buf = new byte[BUFFER_SIZE];
      int bufLen = 0;
      final double fac;
      final int shift;

      public void compute() throws IOException
      {
         out.format("P4\n%d %d\n",size,size);
         for (int y = 0; y<size; y++)
            computeRow(y);
         out.write( buf, 0, bufLen);
         out.close();
      }

      private void computeRow(int y) throws IOException
      {
         int bits = 0;

         final double Ci = (y*fac - 1.0);
          final byte[] bufLocal = buf;
          for (int x = 0; x<size;x++) {
            double Zr = 0.0;
            double Zi = 0.0;
            double Cr = (x*fac - 1.5);
            int i = 50;
            double ZrN = 0;
            double ZiN = 0;
            do {
               Zi = 2.0 * Zr * Zi + Ci;
               Zr = ZrN - ZiN + Cr;
               ZiN = Zi * Zi;
               ZrN = Zr * Zr;
            } while (!(ZiN + ZrN > 4.0) && --i > 0);

            bits = bits << 1;
            if (i == 0) bits++;

            if (x%8 == 7) {
                bufLocal[bufLen++] = (byte) bits;
                if ( bufLen == BUFFER_SIZE) {
                    out.write(bufLocal, 0, BUFFER_SIZE);
                    bufLen = 0;
                }
               bits = 0;
            }
         }
         if (shift!=0) {
            bits = bits << shift;
            bufLocal[bufLen++] = (byte) bits;
            if ( bufLen == BUFFER_SIZE) {
                out.write(bufLocal, 0, BUFFER_SIZE);
                bufLen = 0;
            }
         }
      }
   }
}