aggregationsWhile

AggregationsWhile is a concept used in data processing and programming to describe performing multiple aggregation operations on a stream or sequence while a given condition holds. It couples the idea of continuous accumulation with a control flow predicate, enabling several metrics to be updated as long as the data meets a defined criterion.

Semantics emphasize an initial state of one or more accumulators (for example, sum, count, min, max, or average). For each incoming item that satisfies the predicate, the accumulators are updated. When the condition becomes false, or a termination signal is issued, the current results are emitted and the accumulators may be reset or the process may restart, depending on the implementation.

Variants typically allow the while-condition to reference the item, the current state, or both. Implementations may support windowing, time-based triggers, or explicit reset boundaries. AggregationsWhile is commonly used in streaming analytics and real-time data processing to maintain ongoing summaries without processing the entire history at once.

Example: in a streaming pipeline, aggregationsWhile could track total sales and the number of transactions for a region while the region remains open. As long as new transactions arrive during open hours, the sum and count grow; when the region closes, the current aggregates are emitted and the state reset for the next period.

See also: aggregation, while loop, streaming analytics, windowing, accumulator.