@SuppressWarnings("unchecked")
 protected CheckTuple createDoubleCheckTuple(double[] fieldValues, int numKeyFields) {
   RTreeCheckTuple<Double> checkTuple =
       new RTreeCheckTuple<Double>(fieldValues.length, numKeyFields);
   for (double v : fieldValues) {
     checkTuple.appendField(v);
   }
   return checkTuple;
 }
 @SuppressWarnings("unchecked")
 @Override
 protected CheckTuple createIntCheckTuple(int[] fieldValues, int numKeyFields) {
   RTreeCheckTuple<Integer> checkTuple =
       new RTreeCheckTuple<Integer>(fieldValues.length, numKeyFields);
   for (int v : fieldValues) {
     checkTuple.appendField(v);
   }
   return checkTuple;
 }