private void hanning(int size){
  int start=(windowFunction.length - size) / 2;
  int stop=(windowFunction.length + size) / 2;
  double factor=twoPI / (size - 1.0d);
  for (int i=0; start < stop; start++, i++)   windowFunction[i]=0.5 * (1 - Math.cos(factor * i));
}

private void hanning ( int size ) { int start = ( windowFunction . length - size ) / 2 ; int stop = ( windowFunction . length + size ) / 2 ; double factor = twoPI / ( size - 1.0d ) ; for ( int i = 0 ; start < stop ; start ++ , i ++ ) windowFunction [ i ] = 0.5 * ( 1 - Math . cos ( factor * i ) ) ; }
fill an array with the values of a standard hanning window function
