private void init() {

    GenericUDAFBloomFilterEvaluator udafBloomFilter =
        (GenericUDAFBloomFilterEvaluator) vecAggrDesc.getEvaluator();
    expectedEntries = udafBloomFilter.getExpectedEntries();

    bitSetSize = -1;
    byteStream = new ByteArrayOutputStream();

    // Instantiate the ValueProcessor based on the input type
    ColumnVector.Type colVectorType;
    try {
    colVectorType = inputExpression.getOutputColumnVectorType();
    } catch (HiveException e) {
      throw new RuntimeException(e);
    }
    switch (colVectorType) {
    case LONG:
    case DECIMAL_64:
      valueProcessor = new ValueProcessorLong();
      break;
    case DOUBLE:
      valueProcessor = new ValueProcessorDouble();
      break;
    case DECIMAL:
      valueProcessor = new ValueProcessorDecimal();
      break;
    case BYTES:
      valueProcessor = new ValueProcessorBytes();
      break;
    case TIMESTAMP:
      valueProcessor = new ValueProcessorTimestamp();
      break;
    default:
      throw new IllegalStateException("Unsupported column vector type " + colVectorType);
    }
  }
class for storing the current aggregate value.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/aggregates/VectorUDAFBloomFilter.java