Enum renoir::operator::StreamElement

pub enum StreamElement<Out> {
    Item(Out),
    Timestamped(Out, Timestamp),
    Watermark(Timestamp),
    FlushBatch,
    Terminate,
    FlushAndRestart,
}

An element of the stream. This is what enters and exits from the operators.

An operator may need to change the content of a StreamElement (e.g. a Map may change the value of the Item). Usually Watermark and FlushAndRestart are simply forwarded to the next operator in the chain.

In general a stream may be composed of a sequence of this kind:

((Item | Timestamped | Watermark | FlushBatch)* FlushAndRestart)+ Terminate

Variants

Item(Out)

A normal element containing just the value of the message.

Timestamped(Out, Timestamp)

Like Item, but it’s attached with a timestamp, it’s used to ensure the ordering of the messages.

Watermark(Timestamp)

When an operator receives a Watermark with timestamp t, the operator will never see any message with timestamp less or equal to t.

FlushBatch

Flush the internal batch since there will be too much delay till the next message to come.

Terminate

The stream has ended, and the operators should exit as soon as possible.

No messages should be generated by the operator between a FlushAndRestart and a Terminate.

FlushAndRestart

Mark the end of a stream of data.

Note that this does not mean that the entire stream has ended, for example this is used to mark the end of an iteration. Therefore an operator may be prepared to received new data after this message, but should not retain the internal state.

Implementations

impl<Out> StreamElement<Out>

pub fn variant(&self) -> StreamElement<()>

Create a new StreamElement with an Item(()) if self contains an item, otherwise it returns the same variant of self.

pub fn map<NewOut>(self, f: impl FnOnce(Out) -> NewOut) -> StreamElement<NewOut>

Change the type of the element inside the StreamElement.

pub fn variant_str(&self) -> &'static str

A string representation of the variant of this StreamElement.

pub fn timestamp(&self) -> Option<&Timestamp>

A string representation of the variant of this StreamElement.

pub fn add_key<Key>(self, k: Key) -> StreamElement<(Key, Out)>

pub fn value(&self) -> Option<&Out>

impl<Key, Out> StreamElement<(Key, Out)>

pub fn take_key(self) -> (Option<Key>, StreamElement<Out>)

Map a StreamElement<KeyValue(Key, Out)> to a StreamElement<Out>, returning the key if possible

pub fn key(self) -> Option<Key>

Trait Implementations

impl<Out: Clone> Clone for StreamElement<Out>

fn clone(&self) -> StreamElement<Out>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<Out: Debug> Debug for StreamElement<Out>

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

Formats the value using the given formatter.

impl<'de, Out> Deserialize<'de> for StreamElement<Out>

where Out: Deserialize<'de>,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T> From<WindowResult<T>> for StreamElement<T>

fn from(value: WindowResult<T>) -> Self

Converts to this type from the input type.

impl<Out: Ord> Ord for StreamElement<Out>

fn cmp(&self, other: &StreamElement<Out>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl<Out: PartialEq> PartialEq for StreamElement<Out>

fn eq(&self, other: &StreamElement<Out>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<Out: PartialOrd> PartialOrd for StreamElement<Out>

fn partial_cmp(&self, other: &StreamElement<Out>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<Out> Serialize for StreamElement<Out>

where Out: Serialize,

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl<Out: Eq> Eq for StreamElement<Out>

impl<Out> StructuralPartialEq for StreamElement<Out>