Method: internalGetValues(Object)

1: /*
2: * *************************************************************************************************************************************************************
3: *
4: * TheseFoolishThings: Miscellaneous utilities
5: * http://tidalwave.it/projects/thesefoolishthings
6: *
7: * Copyright (C) 2009 - 2024 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.Nonnull;
29: import java.util.Collection;
30: import java.util.Collections;
31: import java.util.HashMap;
32: import java.util.HashSet;
33: import java.util.Set;
34:
35: /***************************************************************************************************************************************************************
36: *
37: * @author Fabrizio Giudici
38: *
39: **************************************************************************************************************************************************************/
40: public class MultiMap<K, V> extends HashMap<K, Set<V>>
41: {
42: private static final long serialVersionUID = 8834342771135005212L;
43:
44: public synchronized void add (@Nonnull final K key, @Nonnull final V value)
45: {
46: internalGetValues(key).add(value);
47: }
48:
49: public synchronized void addAll (@Nonnull final K key, @Nonnull final Collection<? extends V> values)
50: {
51: if (!values.isEmpty())
52: {
53: internalGetValues(key).addAll(values);
54: }
55: }
56:
57: @Nonnull
58: public synchronized Set<V> getValues (@Nonnull final K key)
59: {
60: final var values = get(key);
61: return (values == null) ? Collections.emptySet() : Collections.unmodifiableSet(values);
62: }
63:
64: @Nonnull
65: private Set<V> internalGetValues (@Nonnull final K key)
66: {
67: var values = get(key);
68:
69:• if (values == null)
70: {
71: values = new HashSet<>();
72: put(key, values);
73: }
74:
75: return values;
76: }
77: }