1 /*
2 * Licensed to the Hipparchus project 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 Hipparchus project 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 package org.hipparchus.stat.descriptive;
19
20 import org.hipparchus.exception.NullArgumentException;
21 import org.hipparchus.util.MathUtils;
22
23 /**
24 * An interface for statistics that can aggregate results.
25 *
26 * @param <T> the type of statistic
27 */
28 public interface AggregatableStatistic<T> {
29
30 /**
31 * Aggregates the provided instance into this instance.
32 * <p>
33 * This method can be used to combine statistics computed over partitions or
34 * subsamples - i.e., the value of this instance after this operation should
35 * be the same as if a single statistic would have been applied over the
36 * combined dataset.
37 *
38 * @param other the instance to aggregate into this instance
39 * @throws NullArgumentException if the input is null
40 */
41 void aggregate(T other) throws NullArgumentException;
42
43 /**
44 * Aggregates the results from the provided instances into this instance.
45 * <p>
46 * This method can be used to combine statistics computed over partitions or
47 * subsamples - i.e., the value of this instance after this operation should
48 * be the same as if a single statistic would have been applied over the
49 * combined dataset.
50 *
51 * @param others the other instances to aggregate into this instance
52 * @throws NullArgumentException if either others or any instance is null
53 */
54 @SuppressWarnings("unchecked")
55 default void aggregate(T... others) {
56 MathUtils.checkNotNull(others);
57 for (T other : others) {
58 aggregate(other);
59 }
60 }
61
62 /**
63 * Aggregates the results from the provided instances into this instance.
64 * <p>
65 * This method can be used to combine statistics computed over partitions or
66 * subsamples - i.e., the value of this instance after this operation should
67 * be the same as if a single statistic would have been applied over the
68 * combined dataset.
69 *
70 * @param others the other instances to aggregate into this instance
71 * @throws NullArgumentException if either others or any instance is null
72 */
73 default void aggregate(Iterable<T> others) {
74 MathUtils.checkNotNull(others);
75 for (T other : others) {
76 aggregate(other);
77 }
78 }
79
80 }