001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.math4.legacy.stat.descriptive;
018
019import org.apache.commons.math4.legacy.exception.MathIllegalArgumentException;
020import org.apache.commons.math4.legacy.exception.NotPositiveException;
021import org.apache.commons.math4.legacy.exception.NullArgumentException;
022import org.apache.commons.math4.legacy.exception.NumberIsTooLargeException;
023import org.apache.commons.math4.legacy.exception.util.LocalizedFormats;
024import org.apache.commons.math4.legacy.core.MathArrays;
025
026/**
027 * Abstract base class for implementations of the {@link UnivariateStatistic} interface.
028 * <p>
029 * Provides a default implementation of <code>evaluate(double[]),</code>
030 * delegating to <code>evaluate(double[], int, int)</code> in the natural way.
031 */
032public abstract class AbstractUnivariateStatistic
033    implements UnivariateStatistic {
034
035    /** Stored data. */
036    private double[] storedData;
037
038    /**
039     * {@inheritDoc}
040     */
041    @Override
042    public double evaluate(final double[] values) throws MathIllegalArgumentException {
043        MathArrays.verifyValues(values, 0, 0);
044        return evaluate(values, 0, values.length);
045    }
046
047    /**
048     * {@inheritDoc}
049     */
050    @Override
051    public abstract double evaluate(double[] values, int begin, int length)
052        throws MathIllegalArgumentException;
053
054    /**
055     * {@inheritDoc}
056     */
057    @Override
058    public abstract UnivariateStatistic copy();
059
060    /**
061     * Set the data array.
062     * <p>
063     * The stored value is a copy of the parameter array, not the array itself.
064     * </p>
065     * @param values data array to store (may be null to remove stored data)
066     * @see #evaluate()
067     */
068    public void setData(final double[] values) {
069        storedData = (values == null) ? null : values.clone();
070    }
071
072    /**
073     * Get a copy of the stored data array.
074     * @return copy of the stored data array (may be null)
075     */
076    public double[] getData() {
077        return (storedData == null) ? null : storedData.clone();
078    }
079
080    /**
081     * Get a reference to the stored data array.
082     * @return reference to the stored data array (may be null)
083     */
084    protected double[] getDataRef() {
085        return storedData;
086    }
087
088    /**
089     * Set the data array.  The input array is copied, not referenced.
090     *
091     * @param values data array to store
092     * @param begin the index of the first element to include
093     * @param length the number of elements to include
094     * @throws MathIllegalArgumentException if values is null or the indices
095     * are not valid
096     * @see #evaluate()
097     */
098    public void setData(final double[] values, final int begin, final int length)
099            throws MathIllegalArgumentException {
100        if (values == null) {
101            throw new NullArgumentException(LocalizedFormats.INPUT_ARRAY);
102        }
103
104        if (begin < 0) {
105            throw new NotPositiveException(LocalizedFormats.START_POSITION, begin);
106        }
107
108        if (length < 0) {
109            throw new NotPositiveException(LocalizedFormats.LENGTH, length);
110        }
111
112        if (begin + length > values.length) {
113            throw new NumberIsTooLargeException(LocalizedFormats.SUBARRAY_ENDS_AFTER_ARRAY_END,
114                                                begin + length, values.length, true);
115        }
116        storedData = new double[length];
117        System.arraycopy(values, begin, storedData, 0, length);
118    }
119
120    /**
121     * Returns the result of evaluating the statistic over the stored data.
122     * <p>
123     * The stored array is the one which was set by previous calls to {@link #setData(double[])}.
124     * </p>
125     * @return the value of the statistic applied to the stored data
126     * @throws MathIllegalArgumentException if the stored data array is null
127     */
128    public double evaluate() throws MathIllegalArgumentException {
129        return evaluate(storedData);
130    }
131}