/*
 ***************************************************************************************
 *  Copyright (C) 2006 EsperTech, Inc. All rights reserved.                            *
 *  http://www.espertech.com/esper                                                     *
 *  http://www.espertech.com                                                           *
 *  ---------------------------------------------------------------------------------- *
 *  The software in this package is published under the terms of the GPL license       *
 *  a copy of which has been included with this distribution in the license.txt file.  *
 ***************************************************************************************
 */
package com.espertech.esper.epl.agg.service;

import com.espertech.esper.epl.expression.core.ExprEvaluator;

/**
 * All aggregation services require evaluation nodes which supply the value to be aggregated (summed, averaged, etc.)
 * and aggregation state factories to make new aggregation states.
 */
public abstract class AggregationServiceBaseGrouped implements AggregationService {
    /**
     * Evaluation nodes under.
     */
    protected ExprEvaluator[] evaluators;

    /**
     * Aggregation states and factories.
     */
    protected AggregationMethodFactory[] aggregators;

    /**
     * Ctor.
     *
     * @param evaluators  - are the child node of each aggregation function used for computing the value to be aggregated
     * @param aggregators - aggregation states/factories
     */
    public AggregationServiceBaseGrouped(ExprEvaluator[] evaluators, AggregationMethodFactory[] aggregators) {
        this.evaluators = evaluators;
        this.aggregators = aggregators;

        if (evaluators.length != aggregators.length) {
            throw new IllegalArgumentException("Expected the same number of evaluates as computer prototypes");
        }
    }

    public void stop() {
    }

    public AggregationService getContextPartitionAggregationService(int agentInstanceId) {
        return this;
    }
}