@Override
  public VectorExpressionDescriptor.Descriptor getDescriptor() {
    return (new VectorExpressionDescriptor.Builder())
        .setMode(
            VectorExpressionDescriptor.Mode.PROJECTION)
        .setNumArguments(2)
        .setArgumentTypes(
            VectorExpressionDescriptor.ArgumentType.getType(serdeConstants.DATE_TYPE_NAME),
            VectorExpressionDescriptor.ArgumentType.getType(serdeConstants.DATE_TYPE_NAME))
        .setInputExpressionTypes(
            VectorExpressionDescriptor.InputExpressionType.SCALAR,
            VectorExpressionDescriptor.InputExpressionType.COLUMN).build();
  }
Method to evaluate scalar-column operation in vectorized fashion.

@batch a package of rows with each column stored in a vector
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/DateScalarSubtractDateColumn.java