org.jasig.portal.events.aggr.TimedAggregationStatistics.java Source code

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Here is the source code for org.jasig.portal.events.aggr.TimedAggregationStatistics.java

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/**
 * Licensed to Jasig under one or more contributor license
 * agreements. See the NOTICE file distributed with this work
 * for additional information regarding copyright ownership.
 * Jasig licenses this file to you under the Apache License,
 * Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a
 * copy of the License at:
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.jasig.portal.events.aggr;

import org.apache.commons.math3.stat.descriptive.StatisticalSummary;

/**
 * Statistics about an aggregation that includes timing info. All values are
 * returned in nanoseconds
 * 
 * @author Eric Dalquist
 */
public interface TimedAggregationStatistics extends StatisticalSummary {
    /**
     * Returns the sum of the squares of the values that have been added.
     * <p>
     * Double.NaN is returned if no values have been added.
     * </p>
     * @return The sum of squares
     */
    double getSumsq();

    /**
     * Returns the <a href="http://en.wikibooks.org/wiki/Statistics/Summary/Variance">
     * population variance</a> of the values that have been added.
     *
     * <p>Double.NaN is returned if no values have been added.</p>
     *
     * @return the population variance
     */
    double getPopulationVariance();

    /**
     * Returns the geometric mean of the values that have been added.
     * <p>
     * Double.NaN is returned if no values have been added.
     * </p>
     * @return the geometric mean
     */
    double getGeometricMean();

    /**
     * Returns the sum of the logs of the values that have been added.
     * <p>
     * Double.NaN is returned if no values have been added.
     * </p>
     * @return the sum of logs
     */
    double getSumOfLogs();

    /**
     * Returns a statistic related to the Second Central Moment.  Specifically,
     * what is returned is the sum of squared deviations from the sample mean
     * among the values that have been added.
     * <p>
     * Returns <code>Double.NaN</code> if no data values have been added and
     * returns <code>0</code> if there is just one value in the data set.</p>
     * <p>
     * @return second central moment statistic
     */
    double getSecondMoment();
}