# Package org.eclipse.viatra.query.runtime.matchers.psystem.aggregations

- Interface Summary
  Interface | Description
  --- | ---
  IAggregatorFactory | Describes an aggregation operator keyword, potentially with type polymorphism.
  IMultisetAggregationOperator<Domain,Accumulator,AggregateResult> | A single column aggregator is used to incrementally compute the aggregate of a multiset of values according to an aggregator operator.

- Class Summary
  Class | Description
  --- | ---
  AbstractMemorylessAggregationOperator<Domain,AggregateResult> | An aggregation operator that does not store interim results beyond the final aggregated value.
  AbstractMultisetAggregationOperator<Domain,Accumulator,AggregateResult> | Base class for aggregation operators.
  BoundAggregator | Augments an aggregator operator with type bindings for the type of values being aggregated and the aggregate result.

- Annotation Types Summary
  Annotation Type | Description
  --- | ---
  AggregatorType | The aggregator type annotation describes the type constraints for the selected aggregator.