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1
22 package org.jboss.util.collection;
23
24 import java.util.Collection  ;
25 import java.util.Collections ;
26 import java.util.HashSet ;
27 import java.util.Iterator ;
28 import java.util.Set ;
29
30
36 public class LazySet implements Set
37 {
38
39 private Set delegate = Collections.EMPTY_SET;
40
41 public boolean add(Object o)
42 {
43 if (delegate == Collections.EMPTY_SET)
44 {
45 delegate = Collections.singleton(o);
46 return true;
47 }
48 else
49 {
50 if (delegate instanceof HashSet == false)
51 delegate = new HashSet (delegate);
52 return delegate.add(o);
53 }
54 }
55
56 public boolean addAll(Collection c)
57 {
58 if (delegate instanceof HashSet == false)
59 delegate = new HashSet (delegate);
60 return delegate.addAll(c);
61 }
62
63 public void clear()
64 {
65 delegate = Collections.EMPTY_SET;
66 }
67
68 public boolean contains(Object o)
69 {
70 return delegate.contains(o);
71 }
72
73 public boolean containsAll(Collection c)
74 {
75 return delegate.containsAll(c);
76 }
77
78 public boolean isEmpty()
79 {
80 return delegate.isEmpty();
81 }
82
83 public Iterator iterator()
84 {
85 return delegate.iterator();
86 }
87
88 public boolean remove(Object o)
89 {
90 if (delegate instanceof HashSet == false)
91 delegate = new HashSet (delegate);
92 return delegate.remove(o);
93 }
94
95 public boolean removeAll(Collection c)
96 {
97 if (delegate instanceof HashSet == false)
98 delegate = new HashSet (delegate);
99 return delegate.removeAll(c);
100 }
101
102 public boolean retainAll(Collection c)
103 {
104 if (delegate instanceof HashSet == false)
105 delegate = new HashSet (delegate);
106 return delegate.retainAll(c);
107 }
108
109 public int size()
110 {
111 return delegate.size();
112 }
113
114 public Object [] toArray()
115 {
116 return delegate.toArray();
117 }
118
119 public Object [] toArray(Object [] a)
120 {
121 return delegate.toArray(a);
122 }
123 }
124 |
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