subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/aggregators/avg.java


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/*******************************************************************************
 * Copyright (c) 2010-2016, Zoltan Ujhelyi, IncQuery Labs Ltd.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-v20.html.
 * 
 * SPDX-License-Identifier: EPL-2.0
 *******************************************************************************/
package tools.refinery.viatra.runtime.matchers.aggregators;

import tools.refinery.viatra.runtime.matchers.psystem.aggregations.AggregatorType;
import tools.refinery.viatra.runtime.matchers.psystem.aggregations.BoundAggregator;
import tools.refinery.viatra.runtime.matchers.psystem.aggregations.IAggregatorFactory;

/**
 * This aggregator calculates the average of the values of a selected aggregate parameter of a called pattern. The aggregate
 * parameter is selected with the '#' symbol; the aggregate parameter must not be used outside the aggregator call. The
 * other parameters of the call might be bound or unbound; bound parameters limit the matches to consider for the
 * summation.
 * 
 * @since 2.0
 *
 */
@AggregatorType(
        parameterTypes = {Integer.class, Double.class, Long.class},
        returnTypes = {Double.class, Double.class, Double.class})
public final class avg implements IAggregatorFactory {

    @Override
    public BoundAggregator getAggregatorLogic(Class<?> domainClass) {
        if (Integer.class.equals(domainClass))
            return new BoundAggregator(IntegerAverageOperator.INSTANCE, Integer.class, Double.class);
        if (Double.class.equals(domainClass))
            return new BoundAggregator(DoubleAverageOperator.INSTANCE, Double.class, Double.class);
        if (Long.class.equals(domainClass))
            return new BoundAggregator(LongAverageOperator.INSTANCE, Long.class, Double.class);
        else throw new IllegalArgumentException();
    }
}