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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.role.impl;
27  
28  import javax.annotation.concurrent.Immutable;
29  import jakarta.annotation.Nonnull;
30  import java.util.Collections;
31  import java.util.HashMap;
32  import java.util.Map;
33  import java.util.Optional;
34  import java.util.Set;
35  import java.util.concurrent.CopyOnWriteArraySet;
36  import it.tidalwave.role.Aggregate;
37  import lombok.ToString;
38  
39  /***************************************************************************************************************************************************************
40   *
41   * A map-based implementation of {@link Aggregate}.
42   * This is no more a public class; use {@link Aggregate#of(String, Object)} instead.
43   * @stereotype Role
44   *
45   * @param <T>    the type of the aggregate
46   * 
47   * @author  Fabrizio Giudici
48   *
49   **************************************************************************************************************************************************************/
50  @Immutable @ToString
51  public class MapAggregate<T> implements Aggregate<T>
52    {
53      private final Map<String, T> mapByName;
54  
55      /***********************************************************************************************************************************************************
56       * Creates a new instance.
57       **********************************************************************************************************************************************************/
58      public MapAggregate()
59        {
60          this.mapByName = Collections.emptyMap();
61        }
62  
63      /***********************************************************************************************************************************************************
64       * Creates a new instance copying fron a given map.
65       * @param   mapByName the map
66       **********************************************************************************************************************************************************/
67      public MapAggregate (@Nonnull final Map<String, T> mapByName)
68        {
69          this.mapByName = Map.copyOf(mapByName);
70        }
71  
72      /***********************************************************************************************************************************************************
73       * {@inheritDoc}
74       **********************************************************************************************************************************************************/
75      @Override @Nonnull
76      public Optional<T> getByName (@Nonnull final String name)
77        {
78          return Optional.ofNullable(mapByName.get(name));
79        }
80  
81      /***********************************************************************************************************************************************************
82       * {@inheritDoc}
83       **********************************************************************************************************************************************************/
84      @Override @Nonnull
85      public Set<String> getNames()
86        {
87          return new CopyOnWriteArraySet<>(mapByName.keySet());
88        }
89  
90      /***********************************************************************************************************************************************************
91       * {@inheritDoc}
92       **********************************************************************************************************************************************************/
93      @Override @Nonnull
94      public Aggregate<T> with (@Nonnull final String name, @Nonnull final T object)
95        {
96          final Map<String, T> clone = new HashMap<>(mapByName);
97          clone.put(name, object);
98          return new MapAggregate<>(clone);
99        }
100   }