Struct apache_avro::Writer

pub struct Writer<'a, W> { /* private fields */ }

Main interface for writing Avro formatted values.

Implementations

impl<'a, W> Writer<'a, W>

pub fn builder() -> WriterBuilder<'a, ((), (), (), (), ()), W>

Create a builder for building Writer. On the builder, call .schema(...), .writer(...), .codec(...)(optional), .block_size(...)(optional), .user_metadata(...)(optional) to set the values of the fields. Finally, call .build() to create the instance of Writer.

impl<'a, W: Write> Writer<'a, W>

pub fn new(schema: &'a Schema, writer: W) -> Self

Creates a Writer given a Schema and something implementing the io::Write trait to write to. No compression Codec will be used.

pub fn with_codec(schema: &'a Schema, writer: W, codec: Codec) -> Self

Creates a Writer with a specific Codec given a Schema and something implementing the io::Write trait to write to.

pub fn schema(&self) -> &'a Schema

Get a reference to the Schema associated to a Writer.

pub fn append<T: Into<Value>>(&mut self, value: T) -> AvroResult<usize>

Append a compatible value (implementing the ToAvro trait) to a Writer, also performing schema validation.

Return the number of bytes written (it might be 0, see below).

NOTE This function is not guaranteed to perform any actual write, since it relies on internal buffering for performance reasons. If you want to be sure the value has been written, then call flush.

pub fn append_value_ref(&mut self, value: &Value) -> AvroResult<usize>

Append a compatible value to a Writer, also performing schema validation.

Return the number of bytes written (it might be 0, see below).

NOTE This function is not guaranteed to perform any actual write, since it relies on internal buffering for performance reasons. If you want to be sure the value has been written, then call flush.

pub fn append_ser<S: Serialize>(&mut self, value: S) -> AvroResult<usize>

Append anything implementing the Serialize trait to a Writer for serde compatibility, also performing schema validation.

Return the number of bytes written.

NOTE This function is not guaranteed to perform any actual write, since it relies on internal buffering for performance reasons. If you want to be sure the value has been written, then call flush.

pub fn extend<I, T: Into<Value>>(&mut self, values: I) -> AvroResult<usize> where
    I: IntoIterator<Item = T>, 

Extend a Writer with an Iterator of compatible values (implementing the ToAvro trait), also performing schema validation.

Return the number of bytes written.

NOTE This function forces the written data to be flushed (an implicit call to flush is performed).

pub fn extend_ser<I, T: Serialize>(&mut self, values: I) -> AvroResult<usize> where
    I: IntoIterator<Item = T>, 

Extend a Writer with an Iterator of anything implementing the Serialize trait for serde compatibility, also performing schema validation.

Return the number of bytes written.

NOTE This function forces the written data to be flushed (an implicit call to flush is performed).

pub fn extend_from_slice(&mut self, values: &[Value]) -> AvroResult<usize>

Extend a Writer by appending each Value from a slice, while also performing schema validation on each value appended.

Return the number of bytes written.

NOTE This function forces the written data to be flushed (an implicit call to flush is performed).

pub fn flush(&mut self) -> AvroResult<usize>

Flush the content appended to a Writer. Call this function to make sure all the content has been written before releasing the Writer.

Return the number of bytes written.

pub fn into_inner(self) -> AvroResult<W>

Return what the Writer is writing to, consuming the Writer itself.

NOTE This function forces the written data to be flushed (an implicit call to flush is performed).

pub fn add_user_metadata<T: AsRef<[u8]>>(
    &mut self,
    key: String,
    value: T
) -> AvroResult<()>

Adds custom metadata to the file. This method could be used only before adding the first record to the writer.