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11 package org.eclipse.jdt.internal.core.util;
12 import java.lang.ref.ReferenceQueue  ;
13 import java.lang.ref.WeakReference ;
14
15 import org.eclipse.jdt.core.compiler.CharOperation;
16
17
20 public class WeakHashSetOfCharArray {
21
22 public static class HashableWeakReference extends WeakReference {
23 public int hashCode;
24 public HashableWeakReference(char[] referent, ReferenceQueue queue) {
25 super(referent, queue);
26 this.hashCode = CharOperation.hashCode(referent);
27 }
28 public boolean equals(Object obj) {
29 if (!(obj instanceof HashableWeakReference)) return false;
30 char[] referent = (char[]) get();
31 char[] other = (char[]) ((HashableWeakReference) obj).get();
32 if (referent == null) return other == null;
33 return CharOperation.equals(referent, other);
34 }
35 public int hashCode() {
36 return this.hashCode;
37 }
38 public String toString() {
39 char[] referent = (char[]) get();
40 if (referent == null) return "[hashCode=" + this.hashCode + "] <referent was garbage collected>"; return "[hashCode=" + this.hashCode + "] \"" + new String (referent) + '\"'; }
43 }
44
45 HashableWeakReference[] values;
46 public int elementSize; int threshold;
48 ReferenceQueue referenceQueue = new ReferenceQueue ();
49
50 public WeakHashSetOfCharArray() {
51 this(5);
52 }
53
54 public WeakHashSetOfCharArray(int size) {
55 this.elementSize = 0;
56 this.threshold = size; int extraRoom = (int) (size * 1.75f);
58 if (this.threshold == extraRoom)
59 extraRoom++;
60 this.values = new HashableWeakReference[extraRoom];
61 }
62
63
68 public char[] add(char[] array) {
69 cleanupGarbageCollectedValues();
70 int valuesLength = this.values.length,
71 index = (CharOperation.hashCode(array) & 0x7FFFFFFF) % valuesLength;
72 HashableWeakReference currentValue;
73 while ((currentValue = this.values[index]) != null) {
74 char[] referent;
75 if (CharOperation.equals(array, referent = (char[]) currentValue.get())) {
76 return referent;
77 }
78 if (++index == valuesLength) {
79 index = 0;
80 }
81 }
82 this.values[index] = new HashableWeakReference(array, this.referenceQueue);
83
84 if (++this.elementSize > this.threshold)
86 rehash();
87
88 return array;
89 }
90
91 private void addValue(HashableWeakReference value) {
92 char[] array = (char[]) value.get();
93 if (array == null) return;
94 int valuesLength = this.values.length;
95 int index = (value.hashCode & 0x7FFFFFFF) % valuesLength;
96 HashableWeakReference currentValue;
97 while ((currentValue = this.values[index]) != null) {
98 if (CharOperation.equals(array, (char[]) currentValue.get())) {
99 return;
100 }
101 if (++index == valuesLength) {
102 index = 0;
103 }
104 }
105 this.values[index] = value;
106
107 if (++this.elementSize > this.threshold)
109 rehash();
110 }
111
112 private void cleanupGarbageCollectedValues() {
113 HashableWeakReference toBeRemoved;
114 while ((toBeRemoved = (HashableWeakReference) this.referenceQueue.poll()) != null) {
115 int hashCode = toBeRemoved.hashCode;
116 int valuesLength = this.values.length;
117 int index = (hashCode & 0x7FFFFFFF) % valuesLength;
118 HashableWeakReference currentValue;
119 while ((currentValue = this.values[index]) != null) {
120 if (currentValue == toBeRemoved) {
121 int sameHash = index;
123 int current;
124 while ((currentValue = this.values[current = (sameHash + 1) % valuesLength]) != null && currentValue.hashCode == hashCode)
125 sameHash = current;
126 this.values[index] = this.values[sameHash];
127 this.values[sameHash] = null;
128 this.elementSize--;
129 break;
130 }
131 if (++index == valuesLength) {
132 index = 0;
133 }
134 }
135 }
136 }
137
138 public boolean contains(char[] array) {
139 return get(array) != null;
140 }
141
142
146 public char[] get(char[] array) {
147 cleanupGarbageCollectedValues();
148 int valuesLength = this.values.length;
149 int index = (CharOperation.hashCode(array) & 0x7FFFFFFF) % valuesLength;
150 HashableWeakReference currentValue;
151 while ((currentValue = this.values[index]) != null) {
152 char[] referent;
153 if (CharOperation.equals(array, referent = (char[]) currentValue.get())) {
154 return referent;
155 }
156 if (++index == valuesLength) {
157 index = 0;
158 }
159 }
160 return null;
161 }
162
163 private void rehash() {
164 WeakHashSetOfCharArray newHashSet = new WeakHashSetOfCharArray(this.elementSize * 2); newHashSet.referenceQueue = this.referenceQueue;
166 HashableWeakReference currentValue;
167 for (int i = 0, length = this.values.length; i < length; i++)
168 if ((currentValue = this.values[i]) != null)
169 newHashSet.addValue(currentValue);
170
171 this.values = newHashSet.values;
172 this.threshold = newHashSet.threshold;
173 this.elementSize = newHashSet.elementSize;
174 }
175
176
180 public char[] remove(char[] array) {
181 cleanupGarbageCollectedValues();
182 int valuesLength = this.values.length;
183 int index = (CharOperation.hashCode(array) & 0x7FFFFFFF) % valuesLength;
184 HashableWeakReference currentValue;
185 while ((currentValue = this.values[index]) != null) {
186 char[] referent;
187 if (CharOperation.equals(array, referent = (char[]) currentValue.get())) {
188 this.elementSize--;
189 this.values[index] = null;
190 rehash();
191 return referent;
192 }
193 if (++index == valuesLength) {
194 index = 0;
195 }
196 }
197 return null;
198 }
199
200 public int size() {
201 return this.elementSize;
202 }
203
204 public String toString() {
205 StringBuffer buffer = new StringBuffer ("{"); for (int i = 0, length = this.values.length; i < length; i++) {
207 HashableWeakReference value = this.values[i];
208 if (value != null) {
209 char[] ref = (char[]) value.get();
210 if (ref != null) {
211 buffer.append('\"');
212 buffer.append(ref);
213 buffer.append("\", "); }
215 }
216 }
217 buffer.append("}"); return buffer.toString();
219 }
220 }
221 |
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