Group.java

1 
/*
2 
 * Copyright 2014-2026 Grzegorz Piwowarek, https://4comprehension.com/
3 
 *
4 
 * Licensed under the Apache License, Version 2.0 (the "License");
5 
 * you may not use this file except in compliance with the License.
6 
 * You may obtain a copy of the License at
7 
 *
8 
 * https://www.apache.org/licenses/LICENSE-2.0
9 
 *
10 
 * Unless required by applicable law or agreed to in writing, software
11 
 * distributed under the License is distributed on an "AS IS" BASIS,
12 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 
 * See the License for the specific language governing permissions and
14 
 * limitations under the License.
15 
 */
16 
package com.pivovarit.collectors;
17
18 
import java.util.ArrayList;
19 
import java.util.Collections;
20 
import java.util.List;
21 
import java.util.Objects;
22 
import java.util.function.BiFunction;
23
24 
/**
25 
 * Represents a grouping of values under a specific key.
26 
 *
27 
 * @param <K>    the type of the key
28 
 * @param <V>    the type of the values
29 
 * @param key    the key of this group, must not be null
30 
 * @param values the list of values, must not be null
31 
 */
32 
public record Group<K, V>(K key, List<V> values) {
33
34 
    /**
35 
     * Constructs a new {@code Group} instance ensuring key and values are not null.
36 
     *
37 
     * @param key    the key, must not be null
38 
     * @param values the list of values, must not be null
39 
     */
40 
    public Group {
41 
        Objects.requireNonNull(key, "key cannot be null");
42 
        Objects.requireNonNull(values, "values cannot be null");
43 
        values = Collections.unmodifiableList(new ArrayList<>(values));
44 
    }
45
46 
    /**
47 
     * Creates a new {@code Group} instance with the given key and values.
48 
     *
49 
     * @param key    the key, must not be null
50 
     * @param values the list of values, must not be null
51 
     * @param <K>    the type of the key
52 
     * @param <V>    the type of the values
53 
     *
54 
     * @return a new {@code Group} instance
55 
     */
56 
    public static <K, V> Group<K, V> of(K key, List<V> values) {
57 1 1. of : replaced return value with null for com/pivovarit/collectors/Group::of → KILLED
 
        return new Group<>(key, values);
58 
    }
59
60 
    /**
61 
     * Transforms the values in this group using the provided mapper function.
62 
     * <p>
63 
     * The mapper receives both the group's key and each value, allowing transformations
64 
     * that depend on the grouping key.
65 
     *
66 
     * @param mapper the mapping function receiving (key, value), must not be null
67 
     * @param <R>    the target type of the mapped values
68 
     *
69 
     * @return a new {@code Group} instance with the same key and the values produced by applying
70 
     * {@code mapper} to the key and each value in this group
71 
     */
72 
    public <R> Group<K, R> map(BiFunction<? super K, ? super V, ? extends R> mapper) {
73 
        Objects.requireNonNull(mapper, "mapper cannot be null");
74 1 1. map : replaced return value with null for com/pivovarit/collectors/Group::map → KILLED
 
        return new Group<>(key, values.stream()
75 1 1. lambda$map$0 : replaced return value with null for com/pivovarit/collectors/Group::lambda$map$0 → KILLED
 
          .map(v -> (R) mapper.apply(key, v))
76 
          .toList());
77 
    }
78 
}

Mutations

57

1.1
Location : of
Killed by : com.pivovarit.collectors.GroupTest.[engine:junit-jupiter]/[class:com.pivovarit.collectors.GroupTest]/[nested-class:MapTest]/[method:mapShouldApplyMapperToAllValues()] replaced return value with null for com/pivovarit/collectors/Group::of → KILLED

74

1.1
Location : map
Killed by : com.pivovarit.collectors.GroupTest.[engine:junit-jupiter]/[class:com.pivovarit.collectors.GroupTest]/[nested-class:MapTest]/[method:mapShouldWorkOnEmptyValuesList()] replaced return value with null for com/pivovarit/collectors/Group::map → KILLED

75

1.1
Location : lambda$map$0
Killed by : com.pivovarit.collectors.GroupTest.[engine:junit-jupiter]/[class:com.pivovarit.collectors.GroupTest]/[nested-class:MapTest]/[method:mapShouldApplyMapperToAllValues()] replaced return value with null for com/pivovarit/collectors/Group::lambda$map$0 → KILLED

Active mutators

Tests examined


Report generated by PIT 1.30.0 support