Struct WindowOperator 

pub struct WindowOperator<S> { /* private fields */ }

A simple window operator keyed only by window time (no grouping key here, for clarity). Maintains state per window and emits results when watermark >= window.end.

Implementations

impl<S> WindowOperator<S>

where S: Clone + Default + Serialize + for<'de> Deserialize<'de> + Send + Sync + 'static,

pub fn new<Init, Red>(assigner: WindowAssigner, init: Init, reduce: Red) -> Self

where Init: Fn() -> S + Send + Sync + 'static, Red: Fn(&mut S, &Value) + Send + Sync + 'static,

pub fn with_backend( self, backend: Arc<dyn KvState>, ns_prefix: impl AsRef<[u8]>, ) -> Self

Configure an external KeyValueState backend for durable window state and a namespace prefix.

pub fn on_element(&mut self, ts: DateTime<Utc>, value: &Value)

pub fn on_watermark(&mut self, watermark: DateTime<Utc>) -> Vec<(Window, S)>

pub async fn restore_from_backend(&mut self) -> Result<()>

where S: for<'de> Deserialize<'de>,

Restore in-memory window states from the backend for this namespace.