Struct arrow::json::reader::ReaderBuilder

pub struct ReaderBuilder { /* fields omitted */ }

JSON file reader builder

Implementations

impl ReaderBuilder

pub fn new() -> Self

Create a new builder for configuring JSON parsing options.

To convert a builder into a reader, call Reader::from_builder

Example

extern crate arrow;

use arrow::json;
use std::fs::File;

fn example() -> json::Reader<File> {
    let file = File::open("test/data/basic.json").unwrap();

    // create a builder, inferring the schema with the first 100 records
    let builder = json::ReaderBuilder::new().infer_schema(Some(100));

    let reader = builder.build::<File>(file).unwrap();

    reader
}

pub fn with_schema(self, schema: SchemaRef) -> Self

Set the JSON file's schema

pub fn infer_schema(self, max_records: Option<usize>) -> Self

Set the JSON reader to infer the schema of the file

pub fn with_batch_size(self, batch_size: usize) -> Self

Set the batch size (number of records to load at one time)

pub fn with_projection(self, projection: Vec<String>) -> Self

Set the reader's column projection

pub fn build<R: Read + Seek>(self, source: R) -> Result<Reader<R>>

Create a new Reader from the ReaderBuilder

Trait Implementations

impl Debug for ReaderBuilder

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

Formats the value using the given formatter.

impl Default for ReaderBuilder

fn default() -> Self

Returns the "default value" for a type.