import type { MediatorExpressionEvaluatorFactory } from '@comunica/bus-expression-evaluator-factory';
import type { IAction, IActorArgs, IActorOutput, IActorTest, Mediate } from '@comunica/core';
import { Actor } from '@comunica/core';
import type { Bindings } from '@comunica/utils-bindings-factory';
import type * as RDF from '@rdfjs/types';
import type { Algebra } from 'sparqlalgebrajs';
/**
 * A comunica actor for creating Binding-Aggregator-factories.
 *
 * Actor types:
 * * Input:  IActionBindingsAggregatorFactory:      A SPARQL expression and a factory for an expression evaluator.
 * * Test:   <none>
 * * Output: IActorBindingsAggregatorFactoryOutput: An aggregator of RDF bindings.
 *
 * @see IActionBindingsAggregatorFactory
 * @see IActorBindingsAggregatorFactoryOutput
 */
export declare abstract class ActorBindingsAggregatorFactory<TS = undefined> extends Actor<IActionBindingsAggregatorFactory, IActorTest, IActorBindingsAggregatorFactoryOutput, TS> {
    protected readonly mediatorExpressionEvaluatorFactory: MediatorExpressionEvaluatorFactory;
    /**
     * @param args -
     *  \ @defaultNested {<default_bus> a <cc:components/Bus.jsonld#Bus>} bus
     *  \ @defaultNested {Creation of Aggregator failed: none of the configured actors were able to handle ${action.expr.aggregator}} busFailMessage
     */
    protected constructor(args: IActorBindingsAggregatorFactoryArgs<TS>);
}
export interface IActionBindingsAggregatorFactory extends IAction {
    expr: Algebra.AggregateExpression;
}
/**
 * Instances of this interface perform a specific aggregation of bindings.
 * You can put bindings and when all bindings have been put, request the result.
 */
export interface IBindingsAggregator {
    /**
     * Registers bindings to the aggregator. Each binding you put has the ability to change the aggregation result.
     * @param bindings the bindings to put.
     */
    putBindings: (bindings: Bindings) => Promise<void>;
    /**
     * Request the result term of aggregating the bindings you have put in the aggregator.
     * It returns:
     *  - a term if a new result.
     *  - undefined if no new result.
     *  - null if the aggregator is in an error state.
     */
    result: () => RDF.Term | undefined | null;
}
export interface IActorBindingsAggregatorFactoryOutput extends IActorOutput, IBindingsAggregator {
}
export interface IActorBindingsAggregatorFactoryArgs<TS = undefined> extends IActorArgs<IActionBindingsAggregatorFactory, IActorTest, IActorBindingsAggregatorFactoryOutput, TS> {
    mediatorExpressionEvaluatorFactory: MediatorExpressionEvaluatorFactory;
}
export type MediatorBindingsAggregatorFactory = Mediate<IActionBindingsAggregatorFactory, IActorBindingsAggregatorFactoryOutput>;