private void setValue(double doubleValue, int intValue) {
              if ((doubleValue >= minValue) && (doubleValue <= maxValue) && (doubleValue % 1 == 0)) {
                parent.set(index, new IntWritable(intValue));
              } else {
                parent.set(index, null);
              }
            }
ETypeConverter is an easy way to set the converter for the right type.
ql/src/java/org/apache/hadoop/hive/ql/io/parquet/convert/ETypeConverter.java