analytics/math3/src/main/java/org/apache/edgent/analytics/math3/UnivariateAggregate.java

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package org.apache.edgent.analytics.math3;

import org.apache.edgent.function.Supplier;

/**
 * Univariate aggregate for a tuple.
 * This is the declaration of the aggregate that
 * application use when declaring a org.apache.edgent.org.apache.edgent.topology.
 * <P>
 * Implementations are typically enums such
 * as {@link org.apache.edgent.analytics.math3.stat.Statistic2 Statistic2}.
 * </P>
 * <P>
 * Each call to {@code get()} must return a new
 * {@link UnivariateAggregator aggregator}
 * that implements the required aggregate.
 * </P>
 * 
 * @see Aggregations
 */
public interface UnivariateAggregate extends Supplier<UnivariateAggregator>{
    
    /**
     * Name of the aggregate.
     * The returned value is used as the JSON key containing
     * the result of the aggregation.
     * @return Name of the aggregate.
     */
    public String name();
}