Java tutorial
/** * Licensed to Apereo under one or more contributor license * agreements. See the NOTICE file distributed with this work * for additional information regarding copyright ownership. * Apereo 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 the following location: * * 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.apereo.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(); }