Struct arrow::array::StructBuilder

pub struct StructBuilder { /* private fields */ }

Array builder for Struct types.

Note that callers should make sure that methods of all the child field builders are properly called to maintain the consistency of the data structure.

Implementations

impl StructBuilder

pub fn new(
    fields: Vec<Field>,
    field_builders: Vec<Box<dyn ArrayBuilder>>
) -> Self

pub fn from_fields(fields: Vec<Field>, capacity: usize) -> Self

pub fn field_builder<T: ArrayBuilder>(&mut self, i: usize) -> Option<&mut T>

Returns a mutable reference to the child field builder at index i. Result will be None if the input type T provided doesn’t match the actual field builder’s type.

pub fn num_fields(&self) -> usize

Returns the number of fields for the struct this builder is building.

pub fn append(&mut self, is_valid: bool) -> Result<()>

Appends an element (either null or non-null) to the struct. The actual elements should be appended for each child sub-array in a consistent way.

pub fn append_null(&mut self) -> Result<()>

Appends a null element to the struct.

pub fn finish(&mut self) -> StructArray

Builds the StructArray and reset this builder.

Trait Implementations

impl ArrayBuilder for StructBuilder

fn len(&self) -> usize

Returns the number of array slots in the builder.

Note that this always return the first child field builder’s length, and it is the caller’s responsibility to maintain the consistency that all the child field builder should have the equal number of elements.

fn is_empty(&self) -> bool

Returns whether the number of array slots is zero

fn finish(&mut self) -> ArrayRef

Builds the array.

fn as_any(&self) -> &dyn Any

Returns the builder as a non-mutable Any reference.

This is most useful when one wants to call non-mutable APIs on a specific builder type. In this case, one can first cast this into a Any, and then use downcast_ref to get a reference on the specific builder.

fn as_any_mut(&mut self) -> &mut dyn Any

Returns the builder as a mutable Any reference.

This is most useful when one wants to call mutable APIs on a specific builder type. In this case, one can first cast this into a Any, and then use downcast_mut to get a reference on the specific builder.

fn into_box_any(self: Box<Self>) -> Box<dyn Any>

Returns the boxed builder as a box of Any.

impl Debug for StructBuilder

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.