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11 package org.eclipse.jdt.internal.compiler.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 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 index = (CharOperation.hashCode(array) & 0x7FFFFFFF) % this.values.length;
71 HashableWeakReference currentValue;
72 while ((currentValue = this.values[index]) != null) {
73 char[] referent;
74 if (CharOperation.equals(array, referent = (char[]) currentValue.get())) {
75 return referent;
76 }
77 index = (index + 1) % this.values.length;
78 }
79 this.values[index] = new HashableWeakReference(array, this.referenceQueue);
80
81 if (++this.elementSize > this.threshold)
83 rehash();
84
85 return array;
86 }
87
88 private void addValue(HashableWeakReference value) {
89 char[] array = (char[]) value.get();
90 if (array == null) return;
91 int valuesLength = this.values.length;
92 int index = (value.hashCode & 0x7FFFFFFF) % valuesLength;
93 HashableWeakReference currentValue;
94 while ((currentValue = this.values[index]) != null) {
95 if (CharOperation.equals(array, (char[]) currentValue.get())) {
96 return;
97 }
98 index = (index + 1) % valuesLength;
99 }
100 this.values[index] = value;
101
102 if (++this.elementSize > this.threshold)
104 rehash();
105 }
106
107 private void cleanupGarbageCollectedValues() {
108 HashableWeakReference toBeRemoved;
109 while ((toBeRemoved = (HashableWeakReference) this.referenceQueue.poll()) != null) {
110 int hashCode = toBeRemoved.hashCode;
111 int valuesLength = this.values.length;
112 int index = (hashCode & 0x7FFFFFFF) % valuesLength;
113 HashableWeakReference currentValue;
114 while ((currentValue = this.values[index]) != null) {
115 if (currentValue == toBeRemoved) {
116 int sameHash = index;
118 int current;
119 while ((currentValue = this.values[current = (sameHash + 1) % valuesLength]) != null && currentValue.hashCode == hashCode)
120 sameHash = current;
121 this.values[index] = this.values[sameHash];
122 this.values[sameHash] = null;
123 this.elementSize--;
124 break;
125 }
126 index = (index + 1) % valuesLength;
127 }
128 }
129 }
130
131 public boolean contains(char[] array) {
132 return get(array) != null;
133 }
134
135
139 public char[] get(char[] array) {
140 cleanupGarbageCollectedValues();
141 int valuesLength = this.values.length;
142 int index = (CharOperation.hashCode(array) & 0x7FFFFFFF) % valuesLength;
143 HashableWeakReference currentValue;
144 while ((currentValue = this.values[index]) != null) {
145 char[] referent;
146 if (CharOperation.equals(array, referent = (char[]) currentValue.get())) {
147 return referent;
148 }
149 index = (index + 1) % valuesLength;
150 }
151 return null;
152 }
153
154 private void rehash() {
155 WeakHashSetOfCharArray newHashSet = new WeakHashSetOfCharArray(this.elementSize * 2); newHashSet.referenceQueue = this.referenceQueue;
157 HashableWeakReference currentValue;
158 for (int i = 0, length = this.values.length; i < length; i++)
159 if ((currentValue = this.values[i]) != null)
160 newHashSet.addValue(currentValue);
161
162 this.values = newHashSet.values;
163 this.threshold = newHashSet.threshold;
164 this.elementSize = newHashSet.elementSize;
165 }
166
167
171 public char[] remove(char[] array) {
172 cleanupGarbageCollectedValues();
173 int valuesLength = this.values.length;
174 int index = (CharOperation.hashCode(array) & 0x7FFFFFFF) % valuesLength;
175 HashableWeakReference currentValue;
176 while ((currentValue = this.values[index]) != null) {
177 char[] referent;
178 if (CharOperation.equals(array, referent = (char[]) currentValue.get())) {
179 this.elementSize--;
180 this.values[index] = null;
181 rehash();
182 return referent;
183 }
184 index = (index + 1) % valuesLength;
185 }
186 return null;
187 }
188
189 public int size() {
190 return this.elementSize;
191 }
192
193 public String toString() {
194 StringBuffer buffer = new StringBuffer ("{"); for (int i = 0, length = this.values.length; i < length; i++) {
196 HashableWeakReference value = this.values[i];
197 if (value != null) {
198 char[] ref = (char[]) value.get();
199 if (ref != null) {
200 buffer.append('\"');
201 buffer.append(ref);
202 buffer.append("\", "); }
204 }
205 }
206 buffer.append("}"); return buffer.toString();
208 }
209 }
210 |
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