1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 /*
19 * This is not the original file distributed by the Apache Software Foundation
20 * It has been modified by the Hipparchus project
21 */
22 package org.hipparchus.stat.descriptive;
23
24 import org.hipparchus.exception.LocalizedCoreFormats;
25 import org.hipparchus.exception.MathIllegalArgumentException;
26 import org.hipparchus.util.MathUtils;
27
28 /**
29 * Abstract base class for implementations of the
30 * {@link UnivariateStatistic} interface.
31 */
32 public abstract class AbstractUnivariateStatistic
33 implements UnivariateStatistic {
34
35 /** Stored data. */
36 private double[] storedData;
37
38 /** Default constructor. */
39 protected AbstractUnivariateStatistic() {
40 // This constructor is intentionally empty. Nothing special is needed here.
41 }
42
43 /**
44 * Copy constructor, creates an identical copy
45 * of the {@code original}.
46 *
47 * @param original the instance to copy
48 * @throws org.hipparchus.exception.NullArgumentException if original is null
49 */
50 protected AbstractUnivariateStatistic(AbstractUnivariateStatistic original) {
51 MathUtils.checkNotNull(original);
52 this.storedData = original.storedData != null ? original.storedData.clone() : null;
53 }
54
55 /** {@inheritDoc} */
56 @Override
57 public abstract double evaluate(double[] values, int begin, int length)
58 throws MathIllegalArgumentException;
59
60 /** {@inheritDoc} */
61 @Override
62 public abstract UnivariateStatistic copy();
63
64 /**
65 * Set the data array.
66 * <p>
67 * The stored value is a copy of the parameter array, not the array itself.
68 * </p>
69 * @param values data array to store (may be null to remove stored data)
70 * @see #evaluate()
71 */
72 public void setData(final double[] values) {
73 storedData = (values == null) ? null : values.clone();
74 }
75
76 /**
77 * Get a copy of the stored data array.
78 * @return copy of the stored data array (may be null)
79 */
80 public double[] getData() {
81 return (storedData == null) ? null : storedData.clone();
82 }
83
84 /**
85 * Get a reference to the stored data array.
86 * @return reference to the stored data array (may be null)
87 */
88 protected double[] getDataRef() {
89 return storedData; // NOPMD - returning an internal array is intentional and documented here
90 }
91
92 /**
93 * Set the data array. The input array is copied, not referenced.
94 *
95 * @param values data array to store
96 * @param begin the index of the first element to include
97 * @param length the number of elements to include
98 * @throws MathIllegalArgumentException if values is null or the indices
99 * are not valid
100 * @see #evaluate()
101 */
102 public void setData(final double[] values, final int begin, final int length)
103 throws MathIllegalArgumentException {
104 MathUtils.checkNotNull(values, LocalizedCoreFormats.INPUT_ARRAY);
105
106 if (begin < 0) {
107 throw new MathIllegalArgumentException(LocalizedCoreFormats.START_POSITION, begin);
108 }
109
110 if (length < 0) {
111 throw new MathIllegalArgumentException(LocalizedCoreFormats.LENGTH, length);
112 }
113
114 if (begin + length > values.length) {
115 throw new MathIllegalArgumentException(LocalizedCoreFormats.SUBARRAY_ENDS_AFTER_ARRAY_END,
116 begin + length, values.length, true);
117 }
118 storedData = new double[length];
119 System.arraycopy(values, begin, storedData, 0, length);
120 }
121
122 /**
123 * Returns the result of evaluating the statistic over the stored data.
124 * <p>
125 * The stored array is the one which was set by previous calls to
126 * {@link #setData(double[])}.
127 *
128 * @return the value of the statistic applied to the stored data
129 * @throws MathIllegalArgumentException if the stored data array is null
130 */
131 public double evaluate() throws MathIllegalArgumentException {
132 return evaluate(storedData);
133 }
134
135 }