1 package org.djutils.immutablecollections;
2
3 import java.util.Collection;
4 import java.util.HashSet;
5 import java.util.Set;
6
7 /**
8 * An immutable wrapper for a HashSet.
9 * <p>
10 * Copyright (c) 2016-2025 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
11 * for project information <a href="https://djutils.org" target="_blank"> https://djutils.org</a>. The DJUTILS project is
12 * distributed under a three-clause BSD-style license, which can be found at
13 * <a href="https://djutils.org/docs/license.html" target="_blank"> https://djutils.org/docs/license.html</a>.
14 * </p>
15 * @author <a href="https://www.tudelft.nl/averbraeck">Alexander Verbraeck</a>
16 * @author <a href="https://www.tudelft.nl/staff/p.knoppers/">Peter Knoppers</a>
17 * @param <E> the type of content of this Set
18 */
19 public class ImmutableHashSet<E> extends ImmutableAbstractSet<E>
20 {
21 /** */
22 private static final long serialVersionUID = 20160507L;
23
24 /**
25 * Construct a new ImmutableHashSet containing a copy of the provided collection.
26 * @param collection the collection to use for the immutable set.
27 */
28 public ImmutableHashSet(final Collection<? extends E> collection)
29 {
30 super(new HashSet<E>(collection), Immutable.COPY);
31 }
32
33 /**
34 * Construct a new ImmutableHashSet containing the provided set.
35 * @param set the set to use for the immutable set.
36 * @param copyOrWrap WRAP stores a pointer to the original collection
37 */
38 public ImmutableHashSet(final Set<E> set, final Immutable copyOrWrap)
39 {
40 super(copyOrWrap == Immutable.COPY ? new HashSet<E>(set) : set, copyOrWrap);
41 }
42
43 /**
44 * Construct a new ImmutableHashSet containing a copy of the provided Collection.
45 * @param collection the collection to use for the immutable set.
46 */
47 public ImmutableHashSet(final ImmutableAbstractCollection<? extends E> collection)
48 {
49 super(new HashSet<E>(collection.getUnderlyingCollection()), Immutable.COPY);
50 }
51
52 /**
53 * Construct a new ImmutableHashSet containing the provided set.
54 * @param set the set to use for the immutable set.
55 * @param copyOrWrap WRAP stores a pointer to the original collection
56 */
57 public ImmutableHashSet(final ImmutableAbstractSet<E> set, final Immutable copyOrWrap)
58 {
59 super(copyOrWrap == Immutable.COPY ? new HashSet<E>(set.getUnderlyingCollection()) : set.getUnderlyingCollection(),
60 copyOrWrap);
61 }
62
63 @Override
64 protected Set<E> getUnderlyingCollection()
65 {
66 return super.getUnderlyingCollection();
67 }
68
69 @Override
70 public final Set<E> toSet()
71 {
72 return new HashSet<E>(getUnderlyingCollection());
73 }
74
75 @Override
76 @SuppressWarnings("checkstyle:designforextension")
77 public String toString()
78 {
79 Set<E> set = getUnderlyingCollection();
80 if (null == set)
81 {
82 return "ImmutableHashSet []";
83 }
84 return "ImmutableHashSet [" + set.toString() + "]";
85 }
86
87 }