Java tutorial
/* Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF 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.apache.edgent.analytics.math3.stat; import org.apache.commons.math3.stat.descriptive.StorelessUnivariateStatistic; import org.apache.commons.math3.stat.descriptive.moment.Mean; import org.apache.commons.math3.stat.descriptive.moment.StandardDeviation; import org.apache.commons.math3.stat.descriptive.rank.Max; import org.apache.commons.math3.stat.descriptive.rank.Min; import org.apache.commons.math3.stat.descriptive.summary.Sum; import org.apache.edgent.analytics.math3.json.JsonAnalytics; import org.apache.edgent.analytics.math3.json.JsonUnivariateAggregate; import org.apache.edgent.analytics.math3.json.JsonUnivariateAggregator; /** * Statistic implementations. * * Univariate statistic aggregate calculations against a value * extracted from a {@code JsonObject}. * * @see JsonAnalytics */ public enum Statistic implements JsonUnivariateAggregate { /** * Calculate the arithmetic mean. * The mean value is represented as a {@code double} * with the key {@code MEAN} in the aggregate result. */ MEAN(new Mean()), /** * Calculate the minimum. * The minimum value is represented as a {@code double} * with the key {@code MIN} in the aggregate result. */ MIN(new Min()), /** * Calculate the maximum. * The maximum value is represented as a {@code double} * with the key {@code MAXIMUM} in the aggregate result. */ MAX(new Max()), /** * Calculate the sum. * The sum is represented as a {@code double} * with the key {@code SUM} in the aggregate result. */ SUM(new Sum()), /** * Calculate the standard deviation. */ STDDEV(new StandardDeviation()); private final StorelessUnivariateStatistic statImpl; private Statistic(StorelessUnivariateStatistic statImpl) { this.statImpl = statImpl; statImpl.clear(); } /** * Return a new instance of this statistic implementation. * @return A new instance of this statistic implementation. */ @Override public JsonUnivariateAggregator get() { return new JsonStorelessStatistic(this, statImpl.copy()); } }