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With inspiration from other libraries
/*
* 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.commons.math3.stat.descriptive;
import org.apache.commons.math3.exception.NotPositiveException;
import org.apache.commons.math3.exception.NullArgumentException;
import org.apache.commons.math3.exception.NumberIsTooLargeException;
import org.apache.commons.math3.exception.MathIllegalArgumentException;
import org.apache.commons.math3.exception.util.LocalizedFormats;
import org.apache.commons.math3.util.MathArrays;
/**
* Abstract base class for all implementations of the
* {@link UnivariateStatistic} interface.
*
* Provides a default implementation of evaluate(double[]),
* delegating to evaluate(double[], int, int) in the natural way.
*
*
* Also includes a test method that performs generic parameter
* validation for the evaluate methods.
*
*/
public abstract class AbstractUnivariateStatistic
implements UnivariateStatistic {
/** Stored data. */
private double[] storedData;
/**
* Set the data array.
*
* The stored value is a copy of the parameter array, not the array itself.
*
* @param values data array to store (may be null to remove stored data)
* @see #evaluate()
*/
public void setData(final double[] values) {
storedData = (values == null) ? null : values.clone();
}
/**
* Get a copy of the stored data array.
* @return copy of the stored data array (may be null)
*/
public double[] getData() {
return (storedData == null) ? null : storedData.clone();
}
/**
* Get a reference to the stored data array.
* @return reference to the stored data array (may be null)
*/
protected double[] getDataRef() {
return storedData;
}
/**
* Set the data array. The input array is copied, not referenced.
*
* @param values data array to store
* @param begin the index of the first element to include
* @param length the number of elements to include
* @throws MathIllegalArgumentException if values is null or the indices
* are not valid
* @see #evaluate()
*/
public void setData(final double[] values, final int begin, final int length)
throws MathIllegalArgumentException {
if (values == null) {
throw new NullArgumentException(LocalizedFormats.INPUT_ARRAY);
}
if (begin < 0) {
throw new NotPositiveException(LocalizedFormats.START_POSITION, begin);
}
if (length < 0) {
throw new NotPositiveException(LocalizedFormats.LENGTH, length);
}
if (begin + length > values.length) {
throw new NumberIsTooLargeException(LocalizedFormats.SUBARRAY_ENDS_AFTER_ARRAY_END,
begin + length, values.length, true);
}
storedData = new double[length];
System.arraycopy(values, begin, storedData, 0, length);
}
/**
* Returns the result of evaluating the statistic over the stored data.
*
* The stored array is the one which was set by previous calls to {@link #setData(double[])}.
*
* @return the value of the statistic applied to the stored data
* @throws MathIllegalArgumentException if the stored data array is null
*/
public double evaluate() throws MathIllegalArgumentException {
return evaluate(storedData);
}
/**
* {@inheritDoc}
*/
public double evaluate(final double[] values) throws MathIllegalArgumentException {
test(values, 0, 0);
return evaluate(values, 0, values.length);
}
/**
* {@inheritDoc}
*/
public abstract double evaluate(final double[] values, final int begin, final int length)
throws MathIllegalArgumentException;
/**
* {@inheritDoc}
*/
public abstract UnivariateStatistic copy();
/**
* This method is used by evaluate(double[], int, int) methods
* to verify that the input parameters designate a subarray of positive length.
*
*
* - returns
true iff the parameters designate a subarray of
* positive length
* - throws
MathIllegalArgumentException if the array is null or
* or the indices are invalid
* - returns
false if the array is non-null, but
* length is 0.
*
*
* @param values the input array
* @param begin index of the first array element to include
* @param length the number of elements to include
* @return true if the parameters are valid and designate a subarray of positive length
* @throws MathIllegalArgumentException if the indices are invalid or the array is null
*/
protected boolean test(
final double[] values,
final int begin,
final int length) throws MathIllegalArgumentException {
return MathArrays.verifyValues(values, begin, length, false);
}
/**
* This method is used by evaluate(double[], int, int) methods
* to verify that the input parameters designate a subarray of positive length.
*
*
* - returns
true iff the parameters designate a subarray of
* non-negative length
* - throws
IllegalArgumentException if the array is null or
* or the indices are invalid
* - returns
false if the array is non-null, but
* length is 0 unless allowEmpty is true
*
*
* @param values the input array
* @param begin index of the first array element to include
* @param length the number of elements to include
* @param allowEmpty if true then zero length arrays are allowed
* @return true if the parameters are valid
* @throws MathIllegalArgumentException if the indices are invalid or the array is null
* @since 3.0
*/
protected boolean test(final double[] values, final int begin,
final int length, final boolean allowEmpty) throws MathIllegalArgumentException {
return MathArrays.verifyValues(values, begin, length, allowEmpty);
}
/**
* This method is used by evaluate(double[], double[], int, int) methods
* to verify that the begin and length parameters designate a subarray of positive length
* and the weights are all non-negative, non-NaN, finite, and not all zero.
*
*
* - returns
true iff the parameters designate a subarray of
* positive length and the weights array contains legitimate values.
* - throws
IllegalArgumentException if any of the following are true:
* - the values array is null
* - the weights array is null
* - the weights array does not have the same length as the values array
* - the weights array contains one or more infinite values
* - the weights array contains one or more NaN values
* - the weights array contains negative values
* - the start and length arguments do not determine a valid array
*
* - returns
false if the array is non-null, but
* length is 0.
*
*
* @param values the input array
* @param weights the weights array
* @param begin index of the first array element to include
* @param length the number of elements to include
* @return true if the parameters are valid and designate a subarray of positive length
* @throws MathIllegalArgumentException if the indices are invalid or the array is null
* @since 2.1
*/
protected boolean test(
final double[] values,
final double[] weights,
final int begin,
final int length) throws MathIllegalArgumentException {
return MathArrays.verifyValues(values, weights, begin, length, false);
}
/**
* This method is used by evaluate(double[], double[], int, int) methods
* to verify that the begin and length parameters designate a subarray of positive length
* and the weights are all non-negative, non-NaN, finite, and not all zero.
*
*
* - returns
true iff the parameters designate a subarray of
* non-negative length and the weights array contains legitimate values.
* - throws
MathIllegalArgumentException if any of the following are true:
* - the values array is null
* - the weights array is null
* - the weights array does not have the same length as the values array
* - the weights array contains one or more infinite values
* - the weights array contains one or more NaN values
* - the weights array contains negative values
* - the start and length arguments do not determine a valid array
*
* - returns
false if the array is non-null, but
* length is 0 unless allowEmpty is true.
*
*
* @param values the input array.
* @param weights the weights array.
* @param begin index of the first array element to include.
* @param length the number of elements to include.
* @param allowEmpty if {@code true} than allow zero length arrays to pass.
* @return {@code true} if the parameters are valid.
* @throws NullArgumentException if either of the arrays are null
* @throws MathIllegalArgumentException if the array indices are not valid,
* the weights array contains NaN, infinite or negative elements, or there
* are no positive weights.
* @since 3.0
*/
protected boolean test(final double[] values, final double[] weights,
final int begin, final int length, final boolean allowEmpty) throws MathIllegalArgumentException {
return MathArrays.verifyValues(values, weights, begin, length, allowEmpty);
}
}