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1
22 package org.jboss.util.collection;
23
24 import java.lang.ref.ReferenceQueue  ;
25 import java.lang.ref.SoftReference ;
26 import java.lang.reflect.Array ;
27 import java.util.Collection ;
28 import java.util.HashMap ;
29 import java.util.Iterator ;
30 import java.util.Set ;
31
32
41 public class SoftSet implements Set
42 {
43 private HashMap map = new HashMap ();
44
45 private ReferenceQueue gcqueue = new ReferenceQueue ();
46
47 static class ComparableSoftReference extends SoftReference
48 {
49 private Integer key;
50 ComparableSoftReference(Integer key, Object o, ReferenceQueue q)
51 {
52 super(o, q);
53 this.key = key;
54 }
55 Integer getKey()
56 {
57 return key;
58 }
59 }
60 static class ComparableSoftReferenceIterator implements Iterator
61 {
62 Iterator theIter;
63 ComparableSoftReferenceIterator(Iterator theIter)
64 {
65 this.theIter = theIter;
66 }
67 public boolean hasNext()
68 {
69 return theIter.hasNext();
70 }
71 public Object next()
72 {
73 ComparableSoftReference csr = (ComparableSoftReference) theIter.next();
74 return csr.get();
75 }
76 public void remove()
77 {
78 theIter.remove();
79 }
80 }
81
82
85 public SoftSet()
86 {
87 }
88
89 public int size()
90 {
91 processQueue();
92 return map.size();
93 }
94
95 public boolean isEmpty()
96 {
97 processQueue();
98 return map.isEmpty();
99 }
100
101 public boolean contains(Object o)
102 {
103 processQueue();
104 Integer key = new Integer (o.hashCode());
105 boolean contains = map.containsKey(key);
106 return contains;
107 }
108
109 public Iterator iterator()
110 {
111 processQueue();
112 Iterator theIter = map.values().iterator();
113 return new ComparableSoftReferenceIterator(theIter);
114 }
115
116 public Object [] toArray()
117 {
118 processQueue();
119 return toArray(new Object [0]);
120 }
121
122 public Object [] toArray(Object [] a)
123 {
124 processQueue();
125 int size = map.size();
126 Object [] array = {};
127 if( a.length >= size )
128 array = a;
129 Iterator iter = map.values().iterator();
130 int index = 0;
131 while( iter.hasNext() )
132 {
133 ComparableSoftReference csr = (ComparableSoftReference) iter.next();
134 Object value = csr.get();
135 if( array.length == 0 )
137 {
138 if( value == null )
139 {
140 index ++;
141 continue;
142 }
143 Array.newInstance(value.getClass(), size);
144 }
145 array[index] = value;
146 index ++;
147 }
148 return array;
149 }
150
151 public boolean add(Object o)
152 {
153 processQueue();
154 Integer key = new Integer (o.hashCode());
155 ComparableSoftReference sr = new ComparableSoftReference(key, o, gcqueue);
156 return map.put(key, sr) == null;
157 }
158
159 public boolean remove(Object o)
160 {
161 processQueue();
162 Integer key = new Integer (o.hashCode());
163 return map.remove(key) != null;
164 }
165
166 public boolean containsAll(Collection c)
167 {
168 processQueue();
169 Iterator iter = c.iterator();
170 boolean contains = true;
171 while( iter.hasNext() )
172 {
173 Object value = iter.next();
174 Integer key = new Integer (value.hashCode());
175 contains &= map.containsKey(key);
176 }
177 return contains;
178 }
179
180 public boolean addAll(Collection c)
181 {
182 processQueue();
183 Iterator iter = c.iterator();
184 boolean added = false;
185 while( iter.hasNext() )
186 {
187 Object value = iter.next();
188 Integer key = new Integer (value.hashCode());
189 ComparableSoftReference sr = new ComparableSoftReference(key, value, gcqueue);
190 added |= map.put(key, sr) == null;
191 }
192 return added;
193 }
194
195 public boolean retainAll(Collection c)
196 {
197 Iterator iter = iterator();
198 boolean removed = false;
199 while( iter.hasNext() )
200 {
201 Object value = iter.next();
202 if( c.contains(value) == false )
203 {
204 iter.remove();
205 removed = true;
206 }
207 }
208 return removed;
209 }
210
211 public boolean removeAll(Collection c)
212 {
213 processQueue();
214 Iterator iter = c.iterator();
215 boolean removed = false;
216 while( iter.hasNext() )
217 {
218 Object value = iter.next();
219 removed |= remove(value);
220 }
221 return removed;
222 }
223
224 public void clear()
225 {
226 while( gcqueue.poll() != null )
227 ;
228 map.clear();
229 }
230
231 public boolean equals(Object o)
232 {
233 return map.equals(o);
234 }
235
236 public int hashCode()
237 {
238 return map.hashCode();
239 }
240
241
245 private void processQueue()
246 {
247 ComparableSoftReference cr;
248 while( (cr = (ComparableSoftReference) gcqueue.poll()) != null )
249 {
250 map.remove(cr.getKey());
251 }
252 }
253
254 }
255 |
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