Struct StreamWriter

pub struct StreamWriter<W> {
    writer: W,
    write_options: IpcWriteOptions,
    finished: bool,
    dictionary_tracker: DictionaryTracker,
    data_gen: IpcDataGenerator,
}

Writer for an IPC stream

Fields

writer: W

The object to write to

write_options: IpcWriteOptions

IPC write options

finished: bool

Whether the writer footer has been written, and the writer is finished

dictionary_tracker: DictionaryTracker

Keeps track of dictionaries that have been written

data_gen: IpcDataGenerator

Implementations

impl<W: Write> StreamWriter<BufWriter<W>>

pub fn try_new_buffered(writer: W, schema: &Schema) -> Result<Self, ArrowError>

Try to create a new stream writer with the writer wrapped in a BufWriter.

See StreamWriter::try_new for an unbuffered version.

impl<W: Write> StreamWriter<W>

pub fn try_new(writer: W, schema: &Schema) -> Result<Self, ArrowError>

Try to create a new writer, with the schema written as part of the header.

Note that there is no internal buffering. See also StreamWriter::try_new_buffered.

Errors

An ‘Err’ may be returned if writing the header to the writer fails.

pub fn try_new_with_options( writer: W, schema: &Schema, write_options: IpcWriteOptions, ) -> Result<Self, ArrowError>

Try to create a new writer with IpcWriteOptions.

Errors

An ‘Err’ may be returned if writing the header to the writer fails.

pub fn write(&mut self, batch: &RecordBatch) -> Result<(), ArrowError>

Write a record batch to the stream

pub fn finish(&mut self) -> Result<(), ArrowError>

Write continuation bytes, and mark the stream as done

pub fn get_ref(&self) -> &W

Gets a reference to the underlying writer.

pub fn get_mut(&mut self) -> &mut W

Gets a mutable reference to the underlying writer.

It is inadvisable to directly write to the underlying writer.

pub fn flush(&mut self) -> Result<(), ArrowError>

Flush the underlying writer.

Both the BufWriter and the underlying writer are flushed.

pub fn into_inner(self) -> Result<W, ArrowError>

Unwraps the the underlying writer.

The writer is flushed and the StreamWriter is finished before returning.

Errors

An ‘Err’ may be returned if an error occurs while finishing the StreamWriter or while flushing the writer.

Example

// The result we expect from an empty schema
let expected = vec![
    255, 255, 255, 255,  48,   0,   0,   0,
     16,   0,   0,   0,   0,   0,  10,   0,
     12,   0,  10,   0,   9,   0,   4,   0,
     10,   0,   0,   0,  16,   0,   0,   0,
      0,   1,   4,   0,   8,   0,   8,   0,
      0,   0,   4,   0,   8,   0,   0,   0,
      4,   0,   0,   0,   0,   0,   0,   0,
    255, 255, 255, 255,   0,   0,   0,   0
];

let schema = Schema::empty();
let buffer: Vec<u8> = Vec::new();
let options = IpcWriteOptions::try_new(8, false, MetadataVersion::V5)?;
let stream_writer = StreamWriter::try_new_with_options(buffer, &schema, options)?;

assert_eq!(stream_writer.into_inner()?, expected);

Trait Implementations

impl<W: Write> RecordBatchWriter for StreamWriter<W>

fn write(&mut self, batch: &RecordBatch) -> Result<(), ArrowError>

Write a single batch to the writer.

fn close(self) -> Result<(), ArrowError>

Write footer or termination data, then mark the writer as done.