Method write

arrow-json/src/writer/mod.rs:377–420

Serialize `batch` to JSON output

(&mut self, batch: &RecordBatch)

    /// Serialize `batch` to JSON output
    pub fn write(&mut self, batch: &RecordBatch) -> Result<(), ArrowError> {
        if batch.num_rows() == 0 {
            return Ok(());
        }

        // BufWriter uses a buffer size of 8KB
        // We therefore double this and flush once we have more than 8KB
        let mut buffer = Vec::with_capacity(16 * 1024);

        let mut is_first_row = !self.started;
        if !self.started {
            self.format.start_stream(&mut buffer)?;
            self.started = true;
        }

        let array = StructArray::from(batch.clone());
        let field = Arc::new(Field::new_struct(
            "",
            batch.schema().fields().clone(),
            false,
        ));

        let mut encoder = make_encoder(&field, &array, &self.options)?;

        // Validate that the root is not nullable
        assert!(!encoder.has_nulls(), "root cannot be nullable");
        for idx in 0..batch.num_rows() {
            self.format.start_row(&mut buffer, is_first_row)?;
            is_first_row = false;

            encoder.encode(idx, &mut buffer);
            if buffer.len() > 8 * 1024 {
                self.writer.write_all(&buffer)?;
                buffer.clear();
            }
            self.format.end_row(&mut buffer)?;
        }

        if !buffer.is_empty() {
            self.writer.write_all(&buffer)?;
        }

        Ok(())
    }

    /// Serialize `batches` to JSON output
    pub fn write_batches(&mut self, batches: &[&RecordBatch]) -> Result<(), ArrowError> {