Struct WindowAggregator 

pub struct WindowAggregator<V, A> { /* private fields */ }

Combines a WindowAssigner, a WindowBuffer, and a user-supplied aggregation function to produce windowed aggregates.

Type parameters

• V – event value type.
• A – aggregate output type.

Implementations

impl<V: Clone, A> WindowAggregator<V, A>

pub fn tumbling<F>(size_ms: u64, aggregate_fn: F) -> Self

where F: Fn(&[V]) -> A + Send + Sync + 'static,

Create a new aggregator using a TumblingWindowAssigner.

• size_ms – window duration in milliseconds.
• aggregate_fn – function from a window’s value slice to an aggregate.

pub fn sliding<F>(size_ms: u64, step_ms: u64, aggregate_fn: F) -> Self

where F: Fn(&[V]) -> A + Send + Sync + 'static,

Create a new aggregator using a SlidingWindowAssigner.

pub fn process_with_bounds(&mut self, bounds: Vec<WindowBound>, value: V)

Process one event: assign to windows and buffer the value.

The caller is responsible for computing the window bounds (e.g. via a WindowAssigner) and passing them here together with the event time.

pub fn process_tumbling(&mut self, size_ms: u64, event_time_ms: i64, value: V)

Process one event using a tumbling window of the configured size.

pub fn advance_watermark(&mut self, watermark_ms: i64) -> Vec<(WindowBound, A)>

Advance the watermark, emitting all expired windows.

Returns a list of (WindowBound, aggregate_value) for every window whose end_ms ≤ watermark_ms.

pub fn current_watermark(&self) -> i64

Return the current watermark.