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20 package org.apache.mina.util;
21
22 import java.util.AbstractSet;
23 import java.util.Collection;
24 import java.util.IdentityHashMap;
25 import java.util.Iterator;
26 import java.util.Map;
27 import java.util.Set;
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35 public class IdentityHashSet<E> extends AbstractSet<E> {
36 private final Map<E, Boolean> delegate = new IdentityHashMap<E, Boolean>();
37
38 public IdentityHashSet() {
39 }
40
41 public IdentityHashSet(Collection<E> c) {
42 addAll(c);
43 }
44
45 @Override
46 public int size() {
47 return delegate.size();
48 }
49
50 @Override
51 public boolean contains(Object o) {
52
53 return delegate.containsKey(o);
54 }
55
56 @Override
57 public Iterator<E> iterator() {
58 return delegate.keySet().iterator();
59 }
60
61 @Override
62 public boolean add(E arg0) {
63 return delegate.put(arg0, Boolean.TRUE) == null;
64 }
65
66 @Override
67 public boolean remove(Object o) {
68
69 return delegate.remove(o) != null;
70 }
71
72 @Override
73 public void clear() {
74 delegate.clear();
75 }
76 }