/*
 * 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
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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 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.
/**
 * Abstract base class for all implementations of the
 * {@link UnivariateStatistic} interface.
 * <p>
 * Provides a default implementation of <code>evaluate(double[]),</code>
 * delegating to <code>evaluate(double[], int, int)</code> in the natural way.
 * </p>
 * <p>
 * Also includes a <code>test</code> method that performs generic parameter
 * validation for the <code>evaluate</code> methods.</p>
 *
 */
public abstract class AbstractUnivariateStatistic
    implements UnivariateStatistic {

    
Stored data. /** Stored data. */
    private double[] storedData;

    
Set the data array.

The stored value is a copy of the parameter array, not the array itself.

Params:
values – data array to store (may be null to remove stored data)
See Also:
evaluate()/**
     * Set the data array.
     * <p>
     * The stored value is a copy of the parameter array, not the array itself.
     * </p>
     * @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.
Returns:
copy of the stored data array (may be null)/**
     * 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.
Returns:
reference to the stored data array (may be null)/**
     * 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.
Params:
values – data array to store
begin – the index of the first element to include
length – the number of elements to include
Throws:
MathIllegalArgumentException – if values is null or the indices
are not valid
See Also:
evaluate()/**
     * 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 setData(double[]). 
Throws:
MathIllegalArgumentException – if the stored data array is null
Returns:
the value of the statistic applied to the stored data/**
     * Returns the result of evaluating the statistic over the stored data.
     * <p>
     * The stored array is the one which was set by previous calls to {@link #setData(double[])}.
     * </p>
     * @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}
/**
     * {@inheritDoc}
     */
    public double evaluate(final double[] values) throws MathIllegalArgumentException {
        test(values, 0, 0);
        return evaluate(values, 0, values.length);
    }

    
{@inheritDoc}
/**
     * {@inheritDoc}
     */
    public abstract double evaluate(final double[] values, final int begin, final int length)
    throws MathIllegalArgumentException;

    
{@inheritDoc}
/**
     * {@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.

Params:
values – the input array
begin – index of the first array element to include
length – the number of elements to include
Throws:
MathIllegalArgumentException – if the indices are invalid or the array is null
Returns:
true if the parameters are valid and designate a subarray of positive length/**
     * This method is used by <code>evaluate(double[], int, int)</code> methods
     * to verify that the input parameters designate a subarray of positive length.
     * <p>
     * <ul>
     * <li>returns <code>true</code> iff the parameters designate a subarray of
     * positive length</li>
     * <li>throws <code>MathIllegalArgumentException</code> if the array is null or
     * or the indices are invalid</li>
     * <li>returns <code>false</li> if the array is non-null, but
     * <code>length</code> is 0.
     * </ul></p>
     *
     * @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

Params:
values – the input array
begin – index of the first array element to include
length – the number of elements to include
allowEmpty – if true then zero length arrays are allowed
Throws:
MathIllegalArgumentException – if the indices are invalid or the array is null
Returns:
true if the parameters are valid
Since:
3.0/**
     * This method is used by <code>evaluate(double[], int, int)</code> methods
     * to verify that the input parameters designate a subarray of positive length.
     * <p>
     * <ul>
     * <li>returns <code>true</code> iff the parameters designate a subarray of
     * non-negative length</li>
     * <li>throws <code>IllegalArgumentException</code> if the array is null or
     * or the indices are invalid</li>
     * <li>returns <code>false</li> if the array is non-null, but
     * <code>length</code> is 0 unless <code>allowEmpty</code> is <code>true</code>
     * </ul></p>
     *
     * @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 <code>true</code> 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.

Params:
values – the input array
weights – the weights array
begin – index of the first array element to include
length – the number of elements to include
Throws:
MathIllegalArgumentException – if the indices are invalid or the array is null
Returns:
true if the parameters are valid and designate a subarray of positive length
Since:
2.1/**
     * This method is used by <code>evaluate(double[], double[], int, int)</code> 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.
     * <p>
     * <ul>
     * <li>returns <code>true</code> iff the parameters designate a subarray of
     * positive length and the weights array contains legitimate values.</li>
     * <li>throws <code>IllegalArgumentException</code> if any of the following are true:
     * <ul><li>the values array is null</li>
     *     <li>the weights array is null</li>
     *     <li>the weights array does not have the same length as the values array</li>
     *     <li>the weights array contains one or more infinite values</li>
     *     <li>the weights array contains one or more NaN values</li>
     *     <li>the weights array contains negative values</li>
     *     <li>the start and length arguments do not determine a valid array</li></ul>
     * </li>
     * <li>returns <code>false</li> if the array is non-null, but
     * <code>length</code> is 0.
     * </ul></p>
     *
     * @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.

Params:
values – the input array.
weights – the weights array.
begin – index of the first array element to include.
length – the number of elements to include.
allowEmpty – if true than allow zero length arrays to pass.
Throws:
NullArgumentException – if either of the arrays are null
MathIllegalArgumentException – if the array indices are not valid,
the weights array contains NaN, infinite or negative elements, or there
are no positive weights.
Returns:
true if the parameters are valid.
Since:
3.0/**
     * This method is used by <code>evaluate(double[], double[], int, int)</code> 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.
     * <p>
     * <ul>
     * <li>returns <code>true</code> iff the parameters designate a subarray of
     * non-negative length and the weights array contains legitimate values.</li>
     * <li>throws <code>MathIllegalArgumentException</code> if any of the following are true:
     * <ul><li>the values array is null</li>
     *     <li>the weights array is null</li>
     *     <li>the weights array does not have the same length as the values array</li>
     *     <li>the weights array contains one or more infinite values</li>
     *     <li>the weights array contains one or more NaN values</li>
     *     <li>the weights array contains negative values</li>
     *     <li>the start and length arguments do not determine a valid array</li></ul>
     * </li>
     * <li>returns <code>false</li> if the array is non-null, but
     * <code>length</code> is 0 unless <code>allowEmpty</code> is <code>true</code>.
     * </ul></p>
     *
     * @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);
    }
}