/*
* Copyright 2004 The Apache Software Foundation.
*
* Licensed 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.commons.math.stat.descriptive;
import java.io.Serializable;
import org.apache.commons.discovery.tools.DiscoverClass;
import org.apache.commons.math.util.MathUtils;
/**
* Abstract factory class for univariate statistical summaries.
*
* @version $Revision: 348519 $ $Date: 2005-11-23 12:12:18 -0700 (Wed, 23 Nov 2005) $
*/
public abstract class SummaryStatistics implements StatisticalSummary, Serializable {
/** Serialization UID */
private static final long serialVersionUID = -6400596334135654825L;
/**
* Create an instance of a <code>SummaryStatistics</code>
*
* @param cls the type of <code>SummaryStatistics</code> object to
* create.
* @return a new factory.
* @throws InstantiationException is thrown if the object can not be
* created.
* @throws IllegalAccessException is thrown if the type's default
* constructor is not accessible.
*/
public static SummaryStatistics newInstance(Class cls) throws
InstantiationException, IllegalAccessException {
return (SummaryStatistics)cls.newInstance();
}
/**
* Create an instance of a <code>SummaryStatistics</code>
*
* @return a new SummaryStatistics instance.
*/
public static SummaryStatistics newInstance() {
SummaryStatistics instance = null;
try {
DiscoverClass dc = new DiscoverClass();
instance = (SummaryStatistics) dc.newInstance(
SummaryStatistics.class,
"org.apache.commons.math.stat.descriptive.SummaryStatisticsImpl");
} catch(Throwable t) {
return new SummaryStatisticsImpl();
}
return instance;
}
/**
* Return a {@link StatisticalSummaryValues} instance reporting current
* statistics.
*
* @return Current values of statistics
*/
public StatisticalSummary getSummary() {
return new StatisticalSummaryValues(getMean(), getVariance(), getN(),
getMax(), getMin(), getSum());
}
/**
* Adds the value to the data to be summarized
* @param v the value to be added
*/
public abstract void addValue(double v);
/**
* Returns the <a href="http://www.xycoon.com/arithmetic_mean.htm">
* arithmetic mean </a> of the available values
* @return The mean or Double.NaN if no values have been added.
*/
public abstract double getMean();
/**
* Returns the <a href="http://www.xycoon.com/geometric_mean.htm">
* geometric mean </a> of the available values
* @return The geometricMean, Double.NaN if no values have been added,
* or if the productof the available values is less than or equal to 0.
*/
public abstract double getGeometricMean();
/**
* Returns the variance of the available values.
* @return The variance, Double.NaN if no values have been added
* or 0.0 for a single value set.
*/
public abstract double getVariance();
/**
* Returns the standard deviation of the available values.
* @return The standard deviation, Double.NaN if no values have been added
* or 0.0 for a single value set.
*/
public abstract double getStandardDeviation();
/**
* Returns the maximum of the available values
* @return The max or Double.NaN if no values have been added.
*/
public abstract double getMax();
/**
* Returns the minimum of the available values
* @return The min or Double.NaN if no values have been added.
*/
public abstract double getMin();
/**
* Returns the number of available values
* @return The number of available values
*/
public abstract long getN();
/**
* Returns the sum of the values that have been added to Univariate.
* @return The sum or Double.NaN if no values have been added
*/
public abstract double getSum();
/**
* Returns the sum of the squares of the available values.
* @return The sum of the squares or Double.NaN if no
* values have been added.
*/
public abstract double getSumsq();
/**
* Resets all statistics
*/
public abstract void clear();
/**
* Returns true iff <code>object</code> is a <code>SummaryStatistics</code>
* instance and all statistics have the same values as this.
* @param object the object to test equality against.
* @return true if object equals this
*/
public boolean equals(Object object) {
if (object == this ) {
return true;
}
if (object instanceof SummaryStatistics == false) {
return false;
}
SummaryStatistics stat = (SummaryStatistics) object;
return (MathUtils.equals(stat.getGeometricMean(),
this.getGeometricMean()) &&
MathUtils.equals(stat.getMax(), this.getMax()) &&
MathUtils.equals(stat.getMean(),this.getMean()) &&
MathUtils.equals(stat.getMin(),this.getMin()) &&
MathUtils.equals(stat.getN(), this.getN()) &&
MathUtils.equals(stat.getSum(), this.getSum()) &&
MathUtils.equals(stat.getSumsq(),this.getSumsq()) &&
MathUtils.equals(stat.getVariance(),this.getVariance()));
}
/**
* Returns hash code based on values of statistics
*
* @return hash code
*/
public int hashCode() {
int result = 31 + MathUtils.hash(getGeometricMean());
result = result * 31 + MathUtils.hash(getGeometricMean());
result = result * 31 + MathUtils.hash(getMax());
result = result * 31 + MathUtils.hash(getMean());
result = result * 31 + MathUtils.hash(getMin());
result = result * 31 + MathUtils.hash(getN());
result = result * 31 + MathUtils.hash(getSum());
result = result * 31 + MathUtils.hash(getSumsq());
result = result * 31 + MathUtils.hash(getVariance());
return result;
}
}