Trait arrow_array::builder::ArrayBuilder

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pub trait ArrayBuilder: Any + Send {
    // Required methods
    fn len(&self) -> usize;
    fn finish(&mut self) -> ArrayRef;
    fn finish_cloned(&self) -> ArrayRef;
    fn as_any(&self) -> &dyn Any;
    fn as_any_mut(&mut self) -> &mut dyn Any;
    fn into_box_any(self: Box<Self>) -> Box<dyn Any>;

    // Provided method
    fn is_empty(&self) -> bool { ... }
}
Expand description

Trait for dealing with different array builders at runtime

Example

// Create

let mut data_builders: Vec<Box<dyn ArrayBuilder>> = vec![
    Box::new(Float64Builder::new()),
    Box::new(Int64Builder::new()),
    Box::new(StringBuilder::new()),
];

// Fill
data_builders[0]
    .as_any_mut()
    .downcast_mut::<Float64Builder>()
    .unwrap()
    .append_value(3.14);
data_builders[1]
    .as_any_mut()
    .downcast_mut::<Int64Builder>()
    .unwrap()
    .append_value(-1);
data_builders[2]
    .as_any_mut()
    .downcast_mut::<StringBuilder>()
    .unwrap()
    .append_value("🍎");

// Finish
let array_refs: Vec<ArrayRef> = data_builders
    .iter_mut()
    .map(|builder| builder.finish())
    .collect();
assert_eq!(array_refs[0].len(), 1);
assert_eq!(array_refs[1].is_null(0), false);
assert_eq!(
    array_refs[2]
        .as_any()
        .downcast_ref::<StringArray>()
        .unwrap()
        .value(0),
    "🍎"
);

Required Methods§

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fn len(&self) -> usize

Returns the number of array slots in the builder

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fn finish(&mut self) -> ArrayRef

Builds the array

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fn finish_cloned(&self) -> ArrayRef

Builds the array without resetting the underlying builder.

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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.

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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.

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

Returns the boxed builder as a box of Any.

Provided Methods§

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fn is_empty(&self) -> bool

Returns whether number of array slots is zero

Implementors§