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1   /*
2    * Copyright (C) 2012 Jean-Christophe Gay (contact@jeanchristophegay.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    *         http://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 org.codehaus.mojo.buildplan.util;
17  
18  import static java.util.stream.Collectors.toList;
19  
20  import java.util.ArrayList;
21  import java.util.Collection;
22  import java.util.LinkedHashMap;
23  import java.util.Map;
24  import java.util.Set;
25  
26  public class LinkedMultimap<K, V> implements Multimap<K, V> {
27  
28      private final Map<K, Collection<V>> map = new LinkedHashMap<>();
29  
30      @Override
31      public Set<K> keySet() {
32          return map.keySet();
33      }
34  
35      @Override
36      public Collection<V> get(K key) {
37          return map.get(key);
38      }
39  
40      @Override
41      public boolean put(K key, V value) {
42          return map.computeIfAbsent(key, k -> new ArrayList<>()).add(value);
43      }
44  
45      @Override
46      public Map<K, Collection<V>> asMap() {
47          return map;
48      }
49  
50      @Override
51      public boolean isEmpty() {
52          return map.isEmpty();
53      }
54  
55      @Override
56      public Collection<V> values() {
57          return map.values().stream().flatMap(Collection::stream).collect(toList());
58      }
59  }