public class IntArrayWritable extends ArrayWritable {
   public IntArrayWritable() { super(IntWritable.class); }
   public IntArrayWritable(int size) {
      super(IntWritable.class);
      IntWritable[] values = new IntWritable[size];
      for (int i=0; i<size; i++) values[i] = new IntWritable();
      set(values);
   }
   public IntWritable itemAt(int index) {
      Writable[] values = get();
      return (IntWritable)values[index];
   }
}