1 /*
2 * *************************************************************************************************************************************************************
3 *
4 * TheseFoolishThings: Miscellaneous utilities
5 * http://tidalwave.it/projects/thesefoolishthings
6 *
7 * Copyright (C) 2009 - 2025 by Tidalwave s.a.s. (http://tidalwave.it)
8 *
9 * *************************************************************************************************************************************************************
10 *
11 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
12 * You may obtain a copy of the License at
13 *
14 * http://www.apache.org/licenses/LICENSE-2.0
15 *
16 * 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
17 * CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
18 *
19 * *************************************************************************************************************************************************************
20 *
21 * git clone https://bitbucket.org/tidalwave/thesefoolishthings-src
22 * git clone https://github.com/tidalwave-it/thesefoolishthings-src
23 *
24 * *************************************************************************************************************************************************************
25 */
26 package it.tidalwave.util.spi;
27
28 import javax.annotation.Nonnull;
29 import java.util.ArrayList;
30 import java.util.Collections;
31 import java.util.List;
32 import java.util.Set;
33 import java.util.function.BiConsumer;
34 import java.util.function.BinaryOperator;
35 import java.util.function.Supplier;
36 import java.util.stream.Collector;
37
38 /***************************************************************************************************************************************************************
39 *
40 * A support {@link Collector} which uses an {@link ArrayList} as the accumulator.
41 *
42 * @param <COLLECTED_TYPE> the type of collected items
43 * @param <COLLECTING_TYPE> the type of collecting item
44 *
45 * @author Fabrizio Giudici
46 *
47 **************************************************************************************************************************************************************/
48 public abstract class ArrayListCollectorSupport<COLLECTED_TYPE, COLLECTING_TYPE>
49 implements Collector<COLLECTED_TYPE, List<COLLECTED_TYPE>, COLLECTING_TYPE>
50 {
51 @Override @Nonnull
52 public Supplier<List<COLLECTED_TYPE>> supplier()
53 {
54 return ArrayList::new;
55 }
56
57 @Override @Nonnull
58 public BiConsumer<List<COLLECTED_TYPE>, COLLECTED_TYPE> accumulator()
59 {
60 return List::add;
61 }
62
63 @Override @Nonnull
64 public BinaryOperator<List<COLLECTED_TYPE>> combiner()
65 {
66 return (left, right) -> { left.addAll(right); return left; };
67 }
68
69 @Override @Nonnull
70 public Set<Characteristics> characteristics()
71 {
72 // Not CONCURRENT since ArrayList is not thread-safe
73 return Collections.emptySet();
74 }
75 }